Johnson -- who has 1,108 yards rushing this year -- became the eighth player in team history to eclipse 1,000 yards in a season. In addition, the Penn State product tied a team record by running for at least 100 yards for the fifth straight game.
Trent Green was 16-of-23 for 253 yards with two touchdowns and a pair of interceptions for the Chiefs (8-4), who have won three straight.
Jake Plummer was 18-of-29 for 276 yards with a touchdown and two interceptions for the Broncos (9-3), who had a four-game winning streak halted and saw their division lead reduced to one game.
Mike Anderson had 103 total yards with two touchdowns in the loss.