This short section of the Nevada gaming regulations answers a lot of questions that are asked from time to time by collectors. It might be a good idea to provide this link on the CC+GTCC web site. The link below is for the PDF version of the regs.

A couple of things I didn't know:

Only two chip sizes are presently authorized 1.55 inches and 1.6875 inches in diameter. Note that the spec is in inches, not in mm as collectors often state.

Destruction of discontinued chips is not mandatory. Only that Gaming agrees with the redemption and disposition plans.

The name of the city and state has to appear on one side of all chips unless Gaming agrees there won't be confusion if it doesn't appear (Mirage for instance).

There is no current regulation on the size of $100 tokens.