They had a $10 million chip -- actually a large rectangular plaque -- which was just a gimmick, plus some other super-high-limit checks for $1 million, $500,000 etc.
But those no longer exist and we very much doubt they ever made it out of the vault other than for publicity shoots.

They do exist. They did make it out of the vault and out of the Aladdlin.

"we learned that other high-end casinos sometimes have chips with a face value of $100,000"
"but these are seldom seen on the floor, since they'd exceed the table limit at most establishments and are simply kept in the vault for paying out large wins."

They are used for betting in high limit salons.