The AFC West is a very strong division. There is a team that is 8-0 (Kansas City Chiefs), a team that is 7-1 (Denver Broncos), a team that is 4-3 (San Diego Chargers), and a team that is 3-4 (Oakland Raiders). Two of these teams are really strong and should definitely be in the playoffs. One team is pretty good and also has a long shot to get into the playoffs, and the last team is just okay.
I'm sorry, to all of you Chiefs fans out there, but I think the Denver Broncos are the better team and will win the division. Peyton Manning is a much better quarterback than Alex Smith. When these two teams go to face each other, I think Broncos are better overall, and Peyton will make sure the Broncos offense adjusts to the good Chiefs defense.
I do think the Chiefs will get one of the Wild Card spots in the playoffs. I don't think the rest of the AFC is good enough to challenge and stop the Chiefs from getting to the playoffs. I believe the Chiefs' first lost will be handed to them by the Denver Broncos in Week 11, because even though the Chiefs defense is good, they have been playing teams that don't have good offenses like the Broncos. The only team that they have played that has a decent offense is the Dallas Cowboys.
The Broncos and the Chiefs should definitely make it into the playoffs. There is a very small chance the Chargers can sneak in too, since they are playing pretty good football right now, but I don't think they actually make it in.