How to fix a stripped metal nut hole on a refrigerator?
Take the bolt to the hardware store, figure out the thread size by screwing it into nuts until you find one that fits. Then go over to the aisle with taps and dies and buy a tap that matches that thread size. 

You'll want to screw that tap into the hole until you meet resistance. 

At the point where you find resistance, you'll want to use a wrench to slowly keep threading the tap into the hole for 2 or 3 turns. This should clean up the bad threads up by re-cutting the metal. Remove the tap and try to thread your handle in again. If it still does not go in all the way, try to tap another 2-3 turns, but be cautious of threading too deep - you may start cutting away at the insulation inside of the refrigerator. 

This process is called "thread chasing," if you'd like to do some more research on the topic.