Is this winning or drawing?

[Pafifi]

[pgn]
[FEN "7q/b1p5/1p1Npkb1/pPP2ppP/P1P5/3B2P1/5P1R/K3R3 w - - 0 1"]

1. hxg6 (1. Nb7) 1. .. Qxh2 *
[/pgn]
The EPD best move is hxg6. However with 1. .. Qxh2 I didn't see a winning path. If it is drawish, what about 1. Nb7, also drawish?

[peter]

[d]7q/b1p5/1p1Npkb1/pPP2ppP/P1P5/3B2P1/5P1R/K3R3 w - - 0 1

That's Mihai Neghina's study Detour, Nr. 4 on his collection- site:

http://chichitza.ro/index.html?lang=en&intro=4

If the lines given by "show solution" aren't enough, try engine Sting for help e.g.

[acase]

[pgn]
[FEN "7q/b1p5/1p1Npkb1/pPP2ppP/P1P5/3B2P1/5P1R/K3R3 w - - 0 1"]

1. hxg6 (1. Nb7) 1. .. Qxh2 *
[/pgn]
The EPD best move is hxg6. However with 1. .. Qxh2 I didn't see a winning path. If it is drawish, what about 1. Nb7, also drawish?

I am pretty sure this is a win here, as the solution from the site that Peter posted looks correct.
The critical point seems to be right here:

[d]q1N5/b1pB4/1pP5/pP2k1p1/P1P5/5PP1/1K6/8 b - - 0 9

Stockfish can't seem to see at this point that black is lost (at least on a quick search).
http://chichitza.ro/Chess.html?lang=en&aux=04

click on "show solution"

[Ovyron]

The critical point seems to be right here:

[d]q1N5/b1pB4/1pP5/pP2k1p1/P1P5/5PP1/1K6/8 b - - 0 9

Oh, I recognize that endgame.

I can confirm that the position is winning and that a human can learn the winning moves and play them against the engine to defeat any defense.