It wasn't just one good season though it was an exceptional breakout season which tells you his potential and it was under a coach which plays to his strengths so it won't surprise me if he hits similar heights under Nagelsmann.
Playing for Bayern we're not really going to know as they dominate 90% of the games the play, and someone like James Tarkowski wouldn't look out of place playing for them in Germany. He has some strengths such as his heading ability, commitments and leadership skills. But he'll always struggle against mobility and pace.