Nagelsmann, whose sacking in March 2023 led to Tuchel's arrival, was tipped to return to Bayern, but has now extended his contract with Germany until 2026
With Monday's victory in their penultimate game, City return to the top of the table with a one point advantage over Liverpool who host Wolverhampton Wanderers on Sunday.
But then Kompany picked up the ball just over the half-way line with the Leicester defence camped deep, and the 33-year-old skipper unleashed a stunning drive from 25 metres out that flew into the top corner of Kasper Schmeichel's goal.
City, who have now won 13 straight league games, have 95 points to Liverpool's 94 and also have a plus four goal difference over Juergen Klopp's side.