Taylor Swift used to crushing it in packed stadiums ... but, it was Travis Kelce's Chiefs which did the crushing Sunday -- dismantling the Raiders while she watched.
The singer-songwriter -- who's kept a low-profile at her future husband's games this season -- was spotted sitting in her private box at the stadium.
It appears she's sitting with her dad, Scott Swift, too ... and, they watched a flaying by the Chiefs -- with one memorable NSFW moment from Patrick Mahomes in the 31-0 victory.