EXCLUSIVE

Robert De Niro has beef with Caesars Palace ... actually he has Kobe beef, because his swanky Nobu restaurant has been stiffed by the house.

De Niro is the co-founder of the high-end restaurant chain and his company, Nobu Hospitality, is listed as a creditor in the bankruptcy case the hotel just filed. According to legal docs -- obtained by TMZ -- Caesars owes Nobu nearly $460K.

And the actor's not alone. According to the docs, Caesars owes Gordon Ramsay $307K. Ramsay also has a restaurant -- Gordon Ramsay Pub & Grill -- in the hotel complex.