Nicky is an antagonist of the film. He is co-lead of the bullies that were against Lucas, but he's copied by Steve from saying anything insulting Lucas to being bullied by him because of it. In the end, he becomes friends with Lucas.
Nicky likes to repeat and follow what others say. He also frequently bullied another kid because of his tendency to follow others. However, he breaks this bad habit and becomes a loyal friend instead, at the end of the film.