Can someone tell me how can this position be winning (for white)?

HanmaYudziro wrote:

Actually Nxf7 is not good move. Computer says best move after e4 e5 Nf3 Nc6 Bc4 Nf6 Ng5 d5 exd5 Nxd5 is d4!! I played hundreds of games by black and always won against Nxf7 line. I can say it is old line of Morphy's century, sorta romantic move :) 7) d4 is the best responce by white. Best regards!

This is very weird. You played hundreds of games of that crappy Nxd5 line, seriously? White is better with d4 and white is also better with Nxf7. Black is not hopelessly lost, but why would you put yourself into such a bad position when much better moves are available?