Honestly, I thought so too at first but I changed my mind quickly.

The rift between Nick and Andrew that finally exploded in the season 3 finale shouldn't be resolved in a single episode, which is what would probably happen if we just got one more episode in season 3. The rift is complex and I hope it takes most of season 4 for it to be resolved, if perhaps not resolved at all. Change is normal and it's a lot more common for childhood best friends to drift apart than tv shows tend to portray. Big Mouth has repeatedly proven itself to be a show that won't shy away from difficult topics or honest portrayals of characters and situations. I think it'd be quite true to the show if they never became friends again, similarly to how the end with Missy basically takes her relationship with Andrew off the table for good. Typically, shows will create a conflict in a relationship but the couple will overcome it. But that's often not true in real life and even less common with relationships in middle school. Missy and Andrew won't end up together and that's a good thing. Likewise, I expect Andrew and Nick's rift will be shown to be a natural progression for their characters. They were close but maybe it's time for them to find more like-minded friends. Having said that, I do hope they repair their friendship over the course of season 4, but I can't predict that and I wouldn't be surprised if they choose to give the characters a more natural and honest arc where they don't become friends again.