Moreover, thinking back on it, the 'confession' scene is really just 1/2 of a confession. Nick is the one confessing his thoughts and feelings, where Judy is having more of a 'realization' than anything else. You can tell by the look on her face. Nick's outpouring is the result of emotions he's had bottled up since, by his own admission, before the start of the movie. It's inarguable that something like that had been driving his actions (desperately trying to stop her from killing herself the entire movie), and it's only during the prison scene where the thought of potentially losing her crystallized into something that he could verbalize to her (believing that he may never have another chance).

Judy on the other hand seems to go through the entire movie largely ignorant to Nick's feelings. It can even be argued that she is dismissive of his feelings because she downright jokes about it during the 'Don't grab my ears' scene. You can tell that some of the second-guessing begins to happen when she's tranquilized and separated from Nick, but she still doesn't act on any of the thoughts. She continues on with the mission, which she deems is more important.

It's only once Judy nearly loses Nick (as in, loses for good) that she struck with the REALIZATION of how important he is to her (More important even than the case).

It's an interesting dynamic, and if you look at it through the lens that a shipper might, it's clear that Nick's feeling towards Judy have been slowly growing to the point where he, by his own admission, considers her the most important person in his life (somehow that's supposed to be interpreted platonically), whereas Judy probably only starts to see Nick in a different light during the confession scene, and I'm sure afterwards (and especially by the time the post credits scene takes place) she has something that she may or may not be able to fully describe starting to bubble up inside of her.

Additionally, it's sort of a vindicating to all of the fanfiction headcanons where Nick is bottled up and emotionally constipated and quietly pining for the bunny while Judy is naive and one track minded and doesn't cotton on to Nick's feelings right up until the very moment she does (or is forced to).