MTV Lawsuit Convict Claims Reality Show Set Him Up in Drug Deal

8/13/2014 12:30 AM PDT

A drug supplier who served more than 7 months for drug-related crimes claims he was set up by MTV's "True Life" ... so he claims in a new lawsuit.

David Nickell says in legal docs -- obtained by TMZ -- he was instructed by a producer on "True Life: I'm Addicted To Pills" to buy pills from a dealer, then give them to a woman on the show ... in front of her 5-year-old son.

Nickell claims the producer told him it would be better TV if the kid was around when the deal went down ... and she assured him he wouldn't get in trouble.

Nickell and the woman who got the pills from him were both arrested after authorities saw the show.  And prosecutors used the video in court to convict him.

He's suing the producer, MTV and its parent company Viacom.