A man has been busted for groping a stranger aboard a Brooklyn train in the middle of the afternoon – then hurling homophobic insults at her and breaking her nose in a brutal beatdown, police said Monday.

Ian Williams, 22, was nabbed Sunday and charged with forcible touching, assault and sexual abuse in the Thursday attack on a J train in Bushwick, cops said.

Williams is accused of grabbing the buttocks of the woman, also 22, on the southbound platform at Broadway and Myrtle Avenue in Bushwick around 1:15 p.m., police said.

The unwanted contact sparked a fight between the two as they got on an arriving train, police said.

Williams threatened the woman, made anti-LGBTQ remarks at her and punched her in the face and body multiple times – causing a nose fracture, authorities said.

He got off the train at the Delancey and Essex street station on the Lower East Side, cops said.

The NYPD on Saturday released a photo of him wearing an orange tracksuit as investigators tried to track him down.

The victim sought medical attention on her own at a local hospital, police said.

The NYPD’s Hate Crime Task Force was notified of the incident, but Williams did not immediately face any hate crime charges, authorities said.

It is unclear how cops tracked down the suspect, who is awaiting arraignment.