Getty Images

A view of the William Hill Sports Book Opening at Ocean Resort Casino on June 28, 2018 in Atlantic City, New Jersey. 

In May, the U.S. Supreme Court ruled that states can legalize sports betting, breaking up Nevada’s monopoly. Two weeks ago, New Jersey Gov. Phil Murphy made the first legal sports wager at Monmouth Park Racetrack. William Hill operates the sports betting at Monmouth and also has the biggest sportsbook in Nevada.

While many more will likely jump into the game, Asher said he’s not worried about competitors.

“We faced really tough competition for years in Nevada. We compete day in and day out against people like MGM, Caesars, Wynn, and so competition is great,” he said. “As long as the rules are fair, we’ll do fine.”

Casinos are hoping the new law will help breathe new life into the industry, which has been hard hit in Atlantic City. Over the last five years, five casinos have shut down as they struggled with increased competition from nearby states.

The Borgata Hotel Casino and Spa became the first casino in the city to accept a legal sports wager on June 14.

Meanwhile, Ocean Resort Casino was one of two new casinos to open in the city on Thursday. The Hard Rock Casino also officially opened just down the boardwalk; however, it is not offering sports betting. It is hoping to attract customers through live entertainment, bringing in big names like Pitbull and Carrie Underwood.

— CNBC's Berkeley Lovelace contributed to this report.