Here's the deal ... Joe has his nickname plastered all over his "REVENGE" fashion collection with Odaingerous streetwear ... but Jeff insists he's owed a cut of the profits.

Jeff's lawyer fired off a cease and desist letter to Odaingerous, obtained by TMZ, claiming he owns the trademark "Joe Exotic." Jeff's threatening a lawsuit if Odaingerous doesn't pull the merch or come to the bargaining table to work out a licensing deal with him.

But, sources close to Odaingerous tell TMZ ... the brand currently has a valid contract with Joe and his team related to the merch, and they claim Jeff's not the true owner of "Joe Exotic."

Jeff sees things much differently ... telling us he's owned and controlled intellectual property with regards to Joe Exotic and Tiger King since 2016. He also raises issue with the fact that Joe has started up a business while behind bars ... something he believes to be illegal.

As you know ... Joe's fashion line keeps selling out, whether it's boxer briefs or hoodies and t-shirts.