In the movie and in early episodes, Cindy had a crush on Nick, due to his coolness and blinding charisma. Often she tried to get his attention only to be ruined by Jimmy and his pranks. However, that ended in Trading Faces when Jimmy made Cindy look like a fool in front of him. Over the course of the show, Nick is revealed to be less cool than the kids initially took him for, and Cindy seems to get over him completely. They do remain friends however.
In a deleted scene for the movie-which was kept in the novelization-Libby and Cindy discuss boys they could probably marry and Cindy denies liking any boys until Libby reminds her about Nick.