The most obvious is 1. ...Qxh2+ 2. Kxh2 Ng3+ 3. Kg1 Rh1#
But I'm pretty sure this is not a forced mate, because the king doesn't have to take the queen sac. 1. ...Qh2+ 2. Kf1 Ng3+ 3. Ke1 and the king escapes. Black is winning fairly easily, but it's no forced mate.
RE: Chess Problem can you find the mate missed by the super GM ?