Four months after PokerStars spent $731 million to settle a Justice Department lawsuit, it is in advanced talks to buy a casino in the hope that New Jersey gambling regulators will let it run online-poker games legally.

The online-poker giant is discussing a deal to buy the struggling Atlantic Club Casino Hotel, formerly the Atlantic City Hilton, from investment firm Colony Capital, several people familiar with the matter said. One of these people said the purchase price being...