Broken welded nut inside frame for motor mount

I was trying to replace the passenger side torque mount on my 98 civic and both nuts that are welded inside the frame snapped off. Now the bolts and nuts just spin.

I’ve read similar posts from people who had to cut an opening in the frame to access the nuts, but I really don’t want to do that. I don’t weld (to have the cut piece put back)

I was looking for other options that match my abilities.

Was wondering what would be safest to do that wouldn’t jeopardize integrity of the frame much:

1. Drill a couple holes just above the nuts on the side of the frame (wheel well side) or
2. Drill holes on the top of the frame under the air box to allow me to use a socket to remove/install.Or
3. Would using rivot nuts be better?

Problem is I’d still need to somehow remove the nuts inside the frame if I go the rivot nut option

Included pics of the mount and top of the frame where the air-box normally sits for reference.