I'm the resident Nick stan
Tinfoil hat time again: I think Tim and Nick have chemistry, like they really do come across as a couple sometimes. I think the stans, who all worship Jenn, see Nick as Jenn's competition. Watching Nick and Tim vs Jenn and Tim, I really think Nick/Tim make the better couple and the stans don't like that. As I said earlier though, Tim seems annoyed by Nick in this video. They do not seem to be having a good time together.
Tim/Nick have a way different thing going on than Tim/Adam. People love to see them together but you never see them described as a bromance.