this is a very good start for him and a good one for the team as a whole, it seems so far that they made a good change, it was unexpected but looks good so far after a win against a tough team like Dortmund and get ahead in the league.
Bayern took a risk to appoint a new coach before such an important match in Bundesliga but that seems to worth it with such beautiful victory against their main opponent Dortmund. 4 - 2 was kinda good result. Dortmund attacked and were somehow successful at the end of the game by scoring 2 goals but weren't able to get a draw.
Bayern got back the first place with 2 points difference from Dortmund. Freiburg, Leipzig and Frankfurt kept the same position with their negative results.
This win was important for Bayern because they took a big risk and appointed Thomas Tuchel instead of Nagelsmann, which was close to the end of the league. Tuchel, on the other hand, managed to equal Borussia Dortmund in his first match. While continuing with 4 different victories until the end of the match, they won 4-2 by conceding 2 goals close to the last minutes.The important thing was to win, and they succeeded. The rest doesn't matter. Now they will try to win both cups at once.