The winner will be announced Monday.
Frost led the Knights to an unbeaten regular season before taking the Nebraska job. He plans to coach No. 10 UCF in the Peach Bowl against Auburn.
Smart, in his second season with Georgia, guided the Bulldogs to a 12-1 record and their first SEC championship since 2005. No. 3 Georgia will face No. 2 Oklahoma in a College Football Playoff game at the Rose Bowl.
Swinney has the defending national champion Tigers back in the playoff for a third straight year. No. 1 Clemson won the Atlantic Coast Conference, finished 12-1, and will face No. 4 Alabama in the Sugar Bowl.