Nezhmetdinov was a little crazy in chess terms. That's why so many people enjoy his games.
White gets two pieces for the queen, and chances on the kingside black squares. Black's d=pawn is backward on an open file, which makes d5 an ideal square for a knight.
Not the most speculative sacrifice of Nezhmetdinov's career.
Generally speaking, it's a draw. Most pawnless endgames are drawn, unless one side has a material advantage of more than a minor piece. Either side can win if there are short-term tactics. To check the outcome of a position, you can use an online tablebase. In particular, it's nice to view the longest wins for either side, which are (according to this page) ...
White doesn't get only one bishop for the queen, but two pieces: a bishop and a knight.
Moreover, Black's weak king, White's domination of the center, great outposts for his pieces and lack of prospects for Black's development (especially his rooks) fully compensate the material imbalance.