Nas' Kidnapped Concert Promoter -- Still In Limbo in Angola

Nas' concert promoter who was kidnapped at gunpoint in Angola is still stuck in the country -- caught in a legal stalemate between Nas and the guy who allegedly kidnapped him .. and it's getting worse by the day.

TMZ broke the story ... Patrick Allocco -- a U.S. concert promoter who booked an Angolan New Year's Eve show starring Nas -- was kidnapped after the Angolan concert promoter sent Allocco a $300,000 advance for Nas and the rapper ended up being a no-show.

We've learned Allocco -- who was released from custody but is still prohibited from leaving the country -- sent Nas the $300k, but now the Angola promoter wants not only the $300,000 back, but an additional $50,000 in expenses.

Here's the deadlock. Nas is willing to send $300,000, but not the addition $50 grand. In addition, before Nas sends ANY money, he wants a letter from both Allocco and the Angolan concert promoter -- releasing him from any liability.