I don't know about Nadler, but some (e.g. Pelosi and Schumer) for sure act one way on the national stage and completely different locally. Trump has different personas too.
One former staffer said Trump is quite demanding on his subordinates. When talking with another, he's very polite and attentive making that person feel like they're the only two while in a very crowded room. He's very quick to flipping at praising people who work for them at the right times.