If you want to send cash through the mail, send it via registered mail. Chips aren't currency, they are collectible substitutes. They are exonumia, items made to be used as money in a situation where it is acceptable to substitute markers (tokens or chips) for cash, and are only acceptable in the establishment named on the item.

Insure every chip and token. USPS will allow it. They won't, as it has been explained to me, allow you to insure the value of cash or a check or money order sent in an ordinary envelope.

Bob