Nick -- acting as a rep for Hulk's estate -- filed the lawsuit on Tuesday in a federal court in Florida ... after Bubba revealed he's going to drop "Video Killed The Radio Star: The Untold Story Of The Hulk Hogan Sex Tape Scandal" later this month.
Nick states the doc -- which promises to tell the real story of how Hulk's romp with Bubba's then-wife, Heather Clem, got leaked to the media -- includes unauthorized images from the sex tape.
In the suit, Nick alleges some of the video was actually played in a trailer that Bubba just recently released.
Nick also claims Bubba -- real name Todd Alan Clem -- has been promoting the documentary using Hulk's trademarks without permission.
Additionally, Nick says releasing the documentary would violate a settlement agreement Bubba and Hulk entered into over the tape back in 2012. The details of the agreement are redacted in the suit.
Nick is suing to stop the release of the documentary and for other unspecified damages.
We've reached out to Bubba for comment, so far no word back yet.
