Brittany Mahomes took time from celebrating the Kansas City Chiefs' return to the Super Bowl to scold the Buffalo fan base ... making it crystal clear she hasn't forgotten about the time Bills Mafia hung a Kermit the Frog puppet dressed as her husband from a pole at a tailgate earlier this season.

"Do we remember this Buffalo? Absolutely disgusting," Patrick's longtime partner said Sunday night. "So as you go home tonight, I pray we become better people."

The incident happened back in November ... when Buffalo hosted the AFC champs at Highmark Stadium in Orchard Park for a big regular season matchup.

Some Bills backers decided to show their team pride by decking out the Muppets character in Mahomes' jersey and a wig -- a clear reference to his signature voice that notably sounds like Kermie -- and proceeded to hang it from a pole for all to see before the contest.

The stunt drew heavy criticism ... given Mahomes is Black.

It mostly went ignored, but after the Chiefs edged the Bills 32-29 to advance to the Super Bowl, Brittany finally broke her silence on the matter.

The Chiefs got the last laugh, though ... as they punched their tickets to New Orleans in hopes of becoming the first team to three-peat.