1...Qxc6?! 2.Rc1 Qd7 3.Qd4 , followed by 4 Rfd1, the d5-pawn turns into a problem for Black.
Now Black is simply better thanks to his extra pawn. Without queens on the board, White's kingside attack is unlikely to succeed.
Unity Chess Club
Narmontas - Sergeev Warsaw (rapid) 2007 Black to move
1...Nxe4 2.Qxe4 Qd5!
Forcing a queen exchange that will finish off White's attack once and for all.