I have both the Colorado and NV regs on chip destruction.
No where in either does it say that chips must be destroyed.
They are to be disposed of in a manner proscribed by the chairman of the GCB.
I don't have the regs in front of me, but the above is close.

If a casino in NV is staying open, the GCB suggests that chips be destroyed. Suggest is a very strong word by the GCB. That is what they did to the Riv Porn chips.

Destruction is a very involved process in NV. Yes, records exist. No, they are not public.

The Fiesta destroyed a rack last year. We held out 52 of the scanned sets. One was donated to the Club auction.