According to Jim Recap: The Crush
Jim decides that he needs to set Dana up with someone to get her out of his house and Andy spots a likely candidate at work one day. The only problem is that Cheryl has a little crush on Nick too. It seems that just about everyone does. He can do anything - he is good looking, he can grill, he can sing, he's just perfect.
So to get back at Cheryl, he invites her to work one day and pretends that he has a crush of his own on the lady that operates the lunch truck. Naturally, Cheryl sees through it and steps up to challenge her to a fight, and Jim, not thinking that it would escalate to something like this, steps in the middle to break it up, his plan in ruins.
Luckily for Jim, Nick is too good for them all. He leaves Dana for the space station at the end of the episode, so it's all good.
