Allie, I feel your pain. My female maroon used to bite me and draw blood. I finally traded her in at the LFS, and she was returned two more times.
IMHO, a 12 gallon nano is far from ideal, but if we're talking just a few days or a week, ok, you could probably get by with it. Where are you storing your LR when you clean the tank out? When I swapped out tanks, I kept my LR in a couple of 30 gallon rubbermaid tubs filled with tank water and a powerhead, and I put my fish in with the rock. Could you get a rubbermaid? I think mine only cost about $6 at Wally World. It doesn't have to be pretty.
But I agree, you will probably have to get rid of her. If you do try your plan, be prepared to rip everything apart and take her out.