Double sided tape would be an expensive temporary fix. Been sort of discussing it in another thread.
I would say:
- Hook fastener tape
- Non-slip tape (like on leading edge of wood steps)
- Possibly spraying some bedliner (let it dry good) on the underside
- Rough up the underside with a belt sander.
- I may strip the underside of an old floor mat and glue it to the underside of the cargo mat so the missing "nubs" are basically - installed.
I used Velcro tape. You just use the hook part on the liner and don't use the other side. It grips pretty good to the carpet. If you take the liner out a lot this will damage carpet over time works really well if you just set and forget.