I'd call. Shorty obviously has a pretty wide range that you're ahead of, and my read would be that the top stack has a decent hand and wants to use his chips to make sure he and he alone gets the privilege of busting the pusher. He knows that his push makes it hard for you to call, which means he probably doesn't want you in the hand, which means he probably doesn't have AA-KK. Sucks if he's got QQ, but it's a chance worth taking, because more likely you'll be in the good side of a coin flip getting a nice overlay.

I'm assuming you're far enough along in the tournament that the pot is significant before the chipleader pushes. If it's still early and you aren't getting a big overlay (ie you'd have to call a bet of 3-4 times the pot), then maybe you could lay down, figuring you don't need to take a coin flip so early.