"Officially" chips from a given casino can only be cashed at
that property. All casinos (that I've visited) have a sign quoting some Federal Law. The signs also state that you can't use personal checks for "gambling purposes", yet most casinos DO cash personal checks
--there is probably some loophole that lets them do it.
I have cashed MGM chips at the Bellagio on a couple of occasions. I could only cash them at the cashier. I could not play the chips. I was told at the cashiers desk that you can cash your chips at the same "family" of hotels but only at the windows.