Which parts of Casino were based on real events? For the most part, the entire film is based on the actual circumstances involving Frank "Lefty" Rosenthal's career in Las Vegas, as well as his relationship with the mob (and the mob's interest in Vegas casinos in the 1970s).
The movie Casino is very closely based on real people and real events. The Tangier casino, in real life, was the Stardust. Sam Rothstein, in real life, was Lefty Rosenthal. Nicky Santoro, in real life, was Tony Spilotro.