Nick Carter's pockets just got lighter ... because we've learned he made a 6-figure settlement with a bouncer who accused the singer of choking him out.
Sources close to the case tell us the settlement fell in the 6-figure range ... and Nick is the one paying the piper.
As for the criminal case ... you'll remember Carter was arrested for misdemeanor battery back in January while partying at a bar in Key West, FL. The battery charge will go away if he completes 25 hours of community service.
Mark DiCowden -- the bouncer's attorney -- says Carter was a "Backstreet thug" who attacked his client for trying to do his job.