Amazing Move

Yesterday I posted this position:

It is an analysis position from a game I was looking at. It is black to move who has both knights currently attacked. Amazingly, he can throw one even further into danger by 1..Nc3!! The resulting positions are difficult to follow and would be a nightmare to work out over the board in a game. Here's some analysis which I would love people to add to, improve upon, or disagree with :)