Plans also call for 1,000 new video-lottery terminals to be added to the existing 5,500 gambling machines.
Construction would take place on a parking lot west of the existing casino. If approvals come, the addition could be completed by April 2019.
Two state agencies, the Franchise Oversight Board, and the New York state Gaming Commission, would need to sign off on any expansion plan. A proposal in 2015 to add terminals operated by Nassau Regional Off-Track Betting Corp. failed.