Chiesa had to be pulled from the UFC 223 card after suffering cuts to his face during the attack. According to TMZ Sports, he's also claiming "severe emotional distress, mental trauma and/or bodily harm" as part of his suit.
Chiesa also included Barclays Center in his lawsuit, alleging the venue didn't do enough to ensure the safety of its patron.
It wasn't specified how much Chiesa is seeking financially from the suit.
New York police arrested McGregor on multiple charges, including two counts of assault and one count of attempted assault. He reached a plea deal with prosecutors in July, pleading guilty to a count of disorderly conduct.
Chiesa wasn't the only fighter hurt during the attack. Ray Borg shared a doctor's note and explained the nature of his injuries:
Ariel Helwani reported for MMA Fighting in April that McGregor was in negotiations with the UFC about his return to the company prior to his attack. In August, the two parties finally reached an agreement that will see McGregor fight Khabib Nurmagomedov at UFC 229 on Oct. 6 in Las Vegas.
It will be McGregor's first bout in the UFC since defeating Eddie Alvarez at UFC 205 in November 2016.