If you picked the Broncos, you are WRONG.
ESPN's site 538 gives the Chiefs a 97 percent chance of making the playoffs and the Broncos a 93 percent chance. The NY Times formula gives the Chiefs a 96 percent chance of making the playoffs and the Broncos have a 90 percent chance.
The Broncos have the better odds of winning the AFC West as of now. It's not difficult, however, to see the Chiefs winning the AFC West. All the Chiefs need to do is beat the Browns and Raiders to end the season and have the Broncos stumble against the Bengals or Chargers.
Both the Chiefs and Broncos also have a six percent shot at the Super Bowl.