Lets say my Thunder golem is on its last click and its my last piece and i push to kill my oppenents last piece is this legal?
if so would i win or my enemy or tie (both had exact armys)

Why wouldn't it be legal?

Your figure attacks, kills opposing figure. Opponent has no figures left on table, game ends. Your figure never even takes the click for pushing because the game ends before then.

Doesn't the pushing damage occur after you make your move? So if thats the case, don't you win?

i am not sure but i would agree with Bald. if you push to attack and it kills you would win before you take push damage. not 100% sure. but that is my guess

Pushing damage is applied at the end of your action. IE, My full health amazon draconum that is tokened makes an an attack on Figure B. I need to roll a 5 to hit. I roll a 5, and I do hit, because I use my stats before the pushing damage is applied. In the same way, the minute the last opposing figure bites it, the game ends and pushing damage is no longer applied.

-Tsetsuki