CNN.com's Jill Martin reported the news Monday, a day after Ngakoue took to Twitter to accuse Incognito of directing a slur at him during the game.
"Great win to day! And 64, you goin have to come harder than some weak racist slurs. I'm proud of my African heritage, as are 70% of the other Black players in this league," Ngakoue tweeted.
Ngakoue said Monday he did not recall if Incognito used the N-word.
"He knows what he said," Ngakoue said, per Michael DiRocco of ESPN. "I don't need to repeat it."
Incognito has not responded to the allegations. He was at the center of a bullying controversy during his time with the Miami Dolphins, verbally abusing then-teammate Jonathan Martin. Ngakoue made reference to Martin in his tweet.
Incognito was accused of using racially insensitive and homophobic language toward Martin during a yearslong period of abuse. He missed the entire 2014 season after the Dolphins released him amid controversy.
The Bills signed him in 2015, and he's played the last three seasons with the team. He has been a Pro Bowl selection all three years in Buffalo.