Snapped off welded nuts inside frame for sway bar bolts

03' Jeep Grand Cherokee. I'm replacing the sway bar on my front end, and the welded nuts inside the frame for the bushing bolts snapped from the frame, so now the bolts are just spinning. Am I better off just grinding the heads off the bolts, pushing them into the frame, and then using self-tapping bolts to reinstall the new sway bar? There are no access holes on the frame, and I would rather not go cutting into the frame.

Assuming you are correct that there is no possible way to access the hole, I would get solution oriented try one of these options:
1. Cut a square access hole to fit a nut and wrench in (I know you don't want to cut, but this may require desperate measures)
2. Drill a small hole near the nut and spot-weld the nut back in from underneath (repeat on a couple corners) - also not desirable because you may weaken part of the frame)
3. Find some way to get inside the frame (either by cutting, or taking parts off), slide a box wrench in to hold the bolt, then crank it down (remember to get the wrench out) - I did this with my back bumper when a nut spun while installing a trailer hitch)
4. Create an opening and drop in "flag nut" - a nut welded to a plate that's large enough that it won't spin (acts like a giant washer and wrench).
I know my response is a bit late from your post. Let us know what you came up with.