How are they captivated? Welded, pressed in, enclosed, swaged?
Picture? I can suggest fix if I know what it is. From what I see on internet, those are swaged or spot welded from the front and there is a recess in the sheet metal to accommodate the flange of the nut? Do you still have them? How many do you need to repair?
This may work Upside down and pop rivet in place.
Also "Rivnuts" or equiv, some need special, expensive tool. You can also just thread a 1/4 thick bar stock and Flat Hd screw/rivet in place.... or you can cut/slice an adjacent hole/slot to receive a
Tinnerman
