She was first mentioned in A Dark Day and 8:30PM as Kim's sister after a hospital explosion left Zoey in critical condition. Kim said that Nicole and Jordan had been away and left Zoey under Kim's care. Zoey eventually pulled through.
Nicole was first seen in Little Bit of Light. She came to visit Kim at the station, and Kim made sure all the desks were tidy and neat before she came. They met happily, and then Nicole met Adam, who tried to introduce himself, she replied that she knew who he was because she had their "engagement photo on my fridge for 8 months". This left Jay and Erin with their mouths open and Ruzek was embarrassed. Later on at home, Kim saw all of Nicole's things packed up in boxes. Nicole said her and Jordan were getting a divorce and moved to Chicago temporarily. Kim had no idea that they were having problems and Nicole said that she didn't tell her everything either, implying she didn't tell her about her and Ruzek getting back together, and then said she wants to forget about Jordan for a while. She then went out at the end of Little Bit of Light to celebrate a friend's birthday.
In Last Minute Resistance, Kim woke up and Nicole wasn't home. She went to work and Ruzek said she was probably out having fun. She then got a phone call from Nicole, who was crying and upset and said she needed Kim's help. Kim immediately tracked down her phone to a train station.