I was in the process of reinstalling the shock nut when the tab on the strut mount support washer broke.

This causes the shock shaft to just rotate. I inserted a 6mm bolt in the threaded hole in the shock to try and use that to help me be able to loosen the nut. It also broke. I can drill the broken bolt out of the shock and use an easy-out to get the bolt out, but I am stumped on a way to get the nut off without cutting the it apart. I am trying to find a nut cracker to do it.
I am thinking the tab got wedged in the threads and now I can't get it loose. I have a new support washer and nut for it once I get it off (or I get the new set of shocks I am wanting).
Any ideas?
Here is what it looks like