NFL superstar wide receiver Brandon Marshall -- who was JUST traded to the Chicago Bears -- has denied punching a woman in the face at a NY nightclub ... despite detailed reports to the contrary.

According to reports, Marshall was outside of a club in Chelsea, NY around 4AM Sunday morning ... when he got into an argument with a group of people ... and allegedly threw a punch that connected with 24-year-old Christin Myles. It's unclear if Marshall intended to strike the woman ... or if she was collateral damage as Brandon was trying to hit someone else .

Either way, Myles says she suffered a black eye ... and filed a police report the next day. According to the NY Post, Myles was nervous about filing because of Brandon's high profile status.

But Marshall's lawyer says the 6'4", 230-pounder did NOT strike Myles ... however, he claims Brandon's wife was injured in a DIFFERENT brawl that went down at the club.

Attorney Harvey Steinberg explains, “While attempting to leave to avoid the melee, [Marshall’s wife] was struck in the face by a thrown bottle. She suffered serious injury." He continued, "The mayhem continued outside.’’