The 'Boomerang' singer was left in the unenviable position of having to choose between two of her own acts on Sunday night (10 November), when Abi Alton and Hannah Barrett fell into the bottom two.
An upset Nicole abstained from voting, leaving the decision of who would go home up to fellow judges Gary Barlow, Sharon Osbourne and Louis Walsh.
The judges seemed surprised by the bottom two – as did teenager Hannah, who looked stunned when the results were announced.
Singer-songwriter Abi, however, was the one who had to say goodbye after Gary and Sharon sent her home. Louis, who didn't need to vote because it was already a majority decision, said he would have followed suit.
Abi burst into tears when she learned her X Factor journey was over although host Dermot O'Leary tried to console her by saying her life would be changed for the better going forward.
She said on Xtra Factor: "I really struggled with my confidences and in my performances and Nicole has helped with that. She takes time when she probably doesn't have it to sit me down and give me advice. I'm so thankful to her for believing in me and bringing me this far."
Despite being visibly upset on the results show, Abi later took to Twitter to tell fans she was remaining positive. "And, as one door closes another one opens," she wrote. Thank you for supporting me on this incredible journey."
Watch Abi Alton sing for survival below:
Nicole, meanwhile, said last night: "I'm pretty gutted, I didn't expect both my girls to be in the bottom two. My favourite part of the whole night is when I saw Abi realise she was singing with Hannah and the look on her face, all she cared about the whole time was Hannah. I think that was beautiful and showed so much about her character."
Abi's departure means that Nicole now has two acts left in her girls category: Hannah and Tamera Foster. Hannah has been in the bottom two twice now while Tamera has been at risk of elimination once.
X Factor continues Saturday night on ITV.