I've seen them installed both ways and it appears the cabinet was countersunk for it but if they are press fit like that I'd definitely want them oriented inward so this can't happen.

If you can get a slot cut into the nut on one side you could use a stout regular screwdriver to hold it steady while unbolting. Maybe even making a bit of a notch by pounding the screwdriver in there, or wedging it from the sides, or in a prying fashion to provide some friction on the nut.

If you do resort to drilling maybe drill it from the head rather than the inside once you get enough of the head meat away it should pop off.

Looked at the pic again, looks like there might already be some nubs on the press fit? If you hold the flat blade screwdriver on the left side of the bolt it should stop it from turning with some pressure. Now, if something is cross threaded from too much tightening you might have to get more drastic.

Great now I have to check mine for replaced ones since the original factory ones which appear to be punched and then have the threads cut (like 3 of them) are usually installed with the punch towards the cab..... and I probably will end up having the same issue the OP is when I go to take the legs off some games.....

Learning something new even after 32 years in the hobby.....