DMX: Breathing Easy Again

DMX has come back from the dead ... performing at a NYC nightclub just days after cops found him unconscious ... not breathing and no pulse.

X took the stage for an hour Thursday night at Lively nightclub, looking strong and healthy.

TMZ broke the story ... DMX was found lying in the parking lot of a Ramada Inn Monday. Cops had to revive him. He denies it was an OD, but a witness told cops the rapper had ingested a white powder, and cops gave him Narcan, an antidote to narcotic ODs.