The school says the move will be announced at a news conference Monday.
The Buffaloes went 11-3 under Nesbitt and beat Indianapolis and Ohio Dominican before losing to Grand Valley State 35-28 on Saturday. West Texas A&M finished third in the Lone Star Conference but had the best overall record and got the league's only playoff bid.
Athletic director Michael McBroom said Carthel was fired Aug. 22 for providing false information to the NCAA. Carthel said he paid for Texas Rangers tickets for two of his players, but they reimbursed him.