Here's a snippet of the end of a game I played recently. As you'll see, Toga II SE analyses Nxd7 as a blunder. Can't see why. If he takes my knight I've got mate, otherwise I win the exchange. Any thoughts?
After 17...Nf5! defending g7 and attacking your queen you lose a piece because he's taking the knight on d7 next. If you then try to fork his pieces with g4 then he pins that pawn with ...Qg6 and he keeps his extra material.