Mad Mex: The Blackfighter (1980)

Mr. Boulois is presented with a key to a Grand Central Station locker containing a million dollars, which will be his if he survives the ordeal. He's then blindfolded, bundled onto a helicopter, and flown to a forested area (supposedly Florida) where he predictably reverts back to his days fighting in 'Nam, using his skill at jungle warfare to turn the tables on his hunters.