You can drill and tap flox as an alternative to a nut plate
Leighton, our local fiberglass guru showed me that a flox mixture (flocked cotton mixed with epoxy) can be drilled an tapped. I secured my wing tip lenses by putting a blob of "flox" on the inside of the corner, and drilling / tapping for #6 screw after the epoxy had cured. Two screws per lens. (Scuff and clean the surface before putting the epoxy on, build a dam with packing tape to help shape the flox mixture if desired).
I'm not recommending this to replace ALL nut plates, but this is a low stress area that is already fiberglass and the drilled / tapped flox works well here.
Regards,