The Chiefs were the NFL's last undefeated team.
The Seahawks snapped a six-game losing skid against the 49ers on Sunday afternoon.
Sitting the past couple weeks might seems to have helped Richardson, who threw and ran the ball well on Sunday and is already back looking like the Colts' QB of the future.
Nix threw for 307 yards and four touchdowns to help keep the Broncos in control of the final playoff berth in the AFC.