Nagelsmann doesn’t need to worry too much yet. Bayern will probably still win the league despite their bad form. There’s only really Dortmund as a proper competitor & they have lots of young players who could choke as the season goes on. Bayern know how to win the big trophies, they have a lot of players with bog experience.
Bayern Munich has already assured Nagelsmann of the support and backing of the management despite their bad form this season, obviously Oliver Khan still believes in Nagelsmann and believes he could turn the situation around in the team so sacking him wouldn't be an option now. They still have hopes of getting better and retaking their place in the league despite the current poor form, they still have chances of still winning the league as they have little competition to face.