The officially sanctioned comic is about Gary Mitchell, too, FYI.
The Gary Mitchell from the alternate reality created by Nero appears in the first two issues of the IDW Star Trek series; having been assigned to the Enterprise on Kirk's request, Mitchell again succumbs to the barrier's influence – a mind-meld performed by Spock confirms that there is no intelligence in Mitchell after the barrier takes over – but during the confrontation on Delta Vega, while Mitchell is tormenting Kirk, he is defeated when Spock sneaks up on the occupied Mitchell and delivers a Vulcan nerve pinch, incapacitating Mitchell long enough for his real self to take over and ask Kirk to kill him. Mitchell is then "killed" by a phaser blast. His body put into a torpedo tube and blasted into space a la Spock in Star Trek II: The Wrath of Khan. The Enterprise leaves Delta Vega's orbit as Mitchell's torpedo tube is left floating in space at the conclusion of this issue.
I'm pretty sure the movie is about Gary Mitchell returning from the dead to terrorize the Federation.