Nwosu attended and played college football at USC under head coaches Steve Sarkisian and Clay Helton.After playing in 12 games during his freshman season, Nwosu was not able to participate in the 2014 Holiday Bowl due to unspecified team rules violations.Head coach Anthony Lynn named Nwosu the backup strongside linebacker to start the regular season, behind veteran Kyle Emanuel.[12] He made his professional regular season debut in the Chargers' season-opening 38-28 loss to the Kansas City Chiefs.On September 16, 2018, Nwosu recorded three combined tackles and made his first career sack during a 31–20 victory at the Buffalo Bills in Week 2.