When Nicole's abusive ex-husband, Trent, is found stabbed to death, Nicole becomes a suspect in the murder, and hires EJ as her lawyer, as well as her divorce lawyer to Victor.. EJ was married to Sami at the time, and he often used Nicole to make Sami jealous. After Sami divorces EJ to be with Lucas, he has sex with Nicole in an elevator, imagining that it is Sami. But due to the encounter, Daniel tells Nicole that she is pregnant. Nicole is shocked, as she was told five years earlier that she would never be able to carry a child to term. She thinks it is a miracle. But unfortunately, she miscarries her and EJ's daughter, and becomes depressed.
To make things worse, she discovers that EJ loves the child, not her. Nicole decides to pretend to be pregnant in order to stay with EJ, so that she is not all alone again. When she finds out EJ is still in love with Sami, she uses "their baby" to remain with the man she loves. Nicole is also upset that EJ got Sami pregnant at the same time she was, and Sami gives birth to a baby girl she names Grace. Nicole switches the baby with another baby she planned on adopting from Mia McCormick, who becomes Grace, and Sami's baby is called Sydney.
Nicole goes into fake labour and "gives birth" to Sydney. She often tells Sydney that she belongs to EJ and her, not Sami. After months of lying to everyone, she finds out that Sami's baby is sick, and dies. Nicole and Sami fight because Nicole will not let her near the child. Sami and EJ become suspicious, but don't look into Nicole's behaviour any futher. Mia returns from Japan and wants to see Nicole, but runs into Tony instead, and accidentally confesses that Sydney is her baby, not Nicole's. Tony confronts Nicole, but is killed before he can warn EJ. On April 21, 2009, Nicole marries EJ. But EJ becomes suspicious of her and sends someone out to follow Nicole.
Then, he hears a conversation between Brady and Nicole about the miscarriage, and he kicks Nicole and Sydney out of the house. Nicole warns Mia, but Chad overhears and wants custody of Sydney. Rafe finds out the truth about the baby switch and reveals it to everyone. Sami and Nicole have a big fight, and the baby is given to EJ and Sami. Nicole points out that Sami considers Sydney "property", and Sydney is loved with Nicole. Sami is furious that Nicole lied to them while watching everyone suffer over the death of Grace, a baby that wasn't even hers. Nicole kidnaps Sydney and goes to Cleveland, but loses her and is arrested. Nicole is imprisoned for 20 years for illegally adopting Mia's baby, and for the baby switch. EJ divorces her while she is in jail. But Nicole remembers that Anna DiMera took Sydney from her, and blackmails Anna into getting Nicole released early.
Nicole returns to Salem, much to everyone's surprise, and gets into a fight with Sami. Upon her return, she gets back together with Brady. Nicole eventually finds out that EJ paid Anna to kidnap Syndey (and make everyone think she died) in order to get revenge on Sami, who hid her pregnancy from him. Nicole tries to blackmail EJ, but he threatens her, so she goes into witness protection program. Rafe seduces Nicole in order to get the tape. Sami, who wants to leave EJ and be with Rafe, sees him kissing Nicole, and decides to marry EJ. But everything is revealed at her wedding to EJ when he plays the confession tape of what EJ did.
Sami breaks up with EJ and decides to be with Rafe. EJ is furious and tries to kill Nicole, but Daniel saves her. Nicole wants to be a part of Sydney's life, and finds out that Sami shot EJ when he was going to take the children. She blackmails Rafe and Sami into letting her be Sydney's babysitter, but they screw it up and the deal ends. She uses Arianna's tape to blackmail EJ: she will be a part of Sydney's life if he gets the tape. He agrees and gets sole custody of Johnny and Sydney. He also forces Nicole to dump Brady, and she does. The two get married as an arrangement for the kids to have a real family.
When Johnny gets cancer, Nicole decides to be a caretaker for him as well. After he is cured, EJ gives Sami and Rafe shared custody. Nicole falls in love with EJ, and he becomes attracted to her as well. But Taylor Raines, Nicole's little sister, returns to Salem, and her and EJ begin an affair. Nicole believes that the two hate each other, but sees them kissing, and gets upset. She discovers that Stefano and EJ have kidnapped Rafe, holding him a prisoner in the basement, and replaced him with an imposter in order to torture Sami. EJ asks for a divorce, insisting Nicole can still be a part of Johnny and Sydney's lives, but she uses this information to force him to remain married to her, causing her to have several fights with EJ and Taylor.
But Nicole realises that she will never mean anything to Sydney, and reunites with Brady. Soon, everything about the imposter is revealed, and Taylor breaks off her recent engagement to EJ. He is devastated, but the two get over each other. EJ is beat up on the pier by Brady, which Nicole discovers. She urges Brady to leave Salem with her in order to escape the feud between the DiMera family and the Kiriakis family. Nicole also catches Taylor and Brady kissing, though they were both drunk. But this makes Nicole see that she and Brady are growing apart as a couple, and are not meant to be. EJ and Nicole realise their feelings for each other, and share a sexy tango, which makes Brady jealous.
When the attacker form the pier holds Nicole hostage, EJ comforts her, and this makes Nicole dump Brady, as she doesn't want to be in a relationship. But EJ hires her as his mayoral campaign manager. Nicole is hesitant but agrees, as long as they only have a professional relationship. But when a blizzard hits Salem in the fall, EJ makes Nicole's favourite dinner, and the two have sex twice, giving into their love. Nicole serves EJ with divorce papers later, making him upset. She tells EJ that they have no future together, making EJ depressed. When his son, Johnny goes missing, Sami comes over to the DiMera mansion and argues with EJ.
Eventually, EJ and Sami have sex out of grief for the son that they believe is dead. However, it is revealed that the dead boy found on the pier is not Johnny, and Johnny is alive. Nicole returns to the mansion, elated about Johnny being alive. She confesses that she will not turn in the divorce papers because she still loves EJ, and the two reconcile. EJ and Sami continue to act strange, as does Will, so Nicole asks EJ if there is something he needs to tell her. But, realizing it would ruin his marriage, and Sami's marriage to Rafe, EJ keeps it a secret.
Rafe finds out eventually, and crashes EJ and Nicole's anniversary night, revealing the truth. Nicole throws her wedding ring at EJ and tells him that she hates him. Daniel returns that night and catches Nicole as she faints. He tells her that she is pregnant. Nicole keeps it a secret, and turns EJ down everytime he tries to get back with her. Rafe and Nicole become friends, and when EJ discovers that Nicole is pregnant, Rafe tells EJ that the baby is his, since EJ saw them "sleeping together" (misunderstanding) in the hotel room. Nicole divorces EJ, and her and Rafe befriend Daniel, though he believes they shouldn't lie to EJ. EJ demands a paternity test.
Nicole and Rafe are furious that EJ moved close to Sami, though it is because he wants to be near his kids. As EJ and Nicole uncover Stefano's betrayal, Nicole comforts EJ, and they nearly kiss before Sami interrupts. When they take the paternity test, EJ reveals his intentions to gain sole custody of the baby. Nicole switches the results with Daniel's help after she and Daniel kiss. EJ is saddened when he finds out that Rafe is, according to the tests, the dad. He asks Nicole to be with him anyway, but she refuses, since she has developed feelings for Rafe and Daniel. EJ continues to think the baby is his child anyway, and soon becomes frustrated with Nicole, and, as Nicole feared, grows closer to Sami, who is now in a relationship with Lucas.
Nicole soon enters into a non-labeled relationship with Daniel, despite her feelings for Rafe. Rafe, Roman and ISA Agent Spencer grow frustrated that they cannot get information out of suspect EJ after Stefano is shot and killed. Nicole says that she can get into EJ's apartment and find evidence, but the officers agree that a search warrant is a better idea. Nicole goes through with the plan anyway, and she goes to EJ's apartment. The two argue over the baby's paternity, but Nicole pretends to faint. EJ is about to call the hospital when Nicole "awakens", and asks for some food and drink. EJ says that he only has alcohol and coffee, so he goes to get Caroline's famous carrot cake. Nicole searches the apartment in his absence, and finds bullets. She hides them before EJ can see anything is wrong, though he thinks she is hiding something.
Nicole shares the cake with EJ, and the baby kicks, causing her to instinctively place EJ's hand on her to feel. They reminisce about the last pregnancy, and EJ gets upset that she is hiding this child from him, just like she lied before. Nicole gets up to leave, but EJ apologizes, begging Nicole for another chance. Nicole makes a snide remark about Sami and leaves. Later, EJ calls the hospital, worrying Nicole that he is onto her and Daniel about the paternity test switch. She is relieved when he says it is merely a memorial for Lexie that he is calling about.
Nicole gives him her condolences, but he makes a snide remark about her friendship with Rafe and Daniel. Nicole gets upset, and EJ later argues with her and Rafe about the baby at the pub. Nicole continues hoping that EJ will never find out the truth of the baby's paternity. Later, she has a run in with EJ, who threatens her. However, Rafe defends Nicole. Later, the truth is revealed about Nicole's manipulations: she made it look like Jennifer killed her baby, even though she knew her baby already died. EJ was horrified to find this out, and even more horrified when Nicole tries to kill herself, though she is saved by Rafe and Daniel.
EJ makes a sad look at her in the hospital, but criticizes her actions the next day. Later, he is dumfounded that Nicole is the church secretary, and that she has changed for the better. He also allows Sydney to send Nicole a thank you message for her Christmas present. Nicole kisses him on New Years to keep him away from Sami, but he doesn't reciprocate, and he asks Will and Sonny to make sure she safely gets back to the church. Later, EJ tells Nicole that he and Sami are back together. Nicole doubts that their reunion will last. She gets closer to Eric Brady. Sami is worried that Nicole will ruin Eric's life, and EJ says that he'll keep an eye on her to make sure that doesn't happen.