He played college football for the Boise State Broncos and was selected by the Tampa Bay Buccaneers in the fifth round of the 2017 NFL draft.

McNichols attended Lakewood High School in Lakewood, California before transferring to Santa Margarita Catholic High School in Rancho Santa Margarita, California for his senior year.

[1] As a youngster, McNichols and fellow NFL player John Ross played in Snoop Dogg's youth football league in Long Beach, California.

[2] He played running back and wide receiver in high school, and his versatility led to him earning the nickname "McWeapon".

[3][4] McNichols enrolled at Boise State in early August 2014 before the start of fall camp.

[6] As a sophomore in 2015, he started 12 games, rushing for 1,337 yards on 240 carries and 20 touchdowns.

[23] On December 3, 2018, McNichols was signed by the Tennessee Titans off the Broncos practice squad.

[29] On May 4, 2020, the Jaguars waived McNichols to make room for veteran running back Chris Thompson.

During the playoffs, McNichols recorded one carry for four yards in the Titans 20–13 loss to the Baltimore Ravens in the wildcard round.

[50] In Week 4 against the Arizona Cardinals, he recorded 8 carries for 68 yards and 2 touchdowns.