You can do that if you can find NM that's rated for use in a Hazardous environment.
Besides, temporary fixes tend to never get done right. As soon as things are jerry-rigged to run, the urgency to getting the thing fixed correctly just sort of goes away. Just look at some of the 'temporary' horror stories on this board.
Those sealing fittings were not designed to have the stuff chipped out of them, so it's a royal PITA to do that.
I think you're stuck replacing the fitting unless you want to spend a lot of grunt work chipping and vacuuming.
