First off, I would absolutely go with Garçon. He will get open down the field. Nnamdi is only a shell of what he once was, and Garçon is faster and stronger than him. He will get open and continue his team-high targets with RGIII back under-center.
Between Wes and Reggie, it has to be Wayne. He has more targets than any receiver in the league, and last week was a fluke. He gets it back together against a really bad Chiefs defense. And keep in mind, the Colts will get the ball early and often because the Chiefs can't keep their offense on the field. Like, at all. Last week the Chiefs had the ball exactly one-half the amount of time as their opponent. That would be laughable... if I wasn't a Jamaal Charles owner
On the other hand, Wekler's production and playmaking have both been on the down-tick consistently since the middle of the season (can someone say 2011 all over again?) Welker's targets and catches are down signifigantly as of late. The former is his fault, and the latter is
really his fault. When Tom Terrific is hitting you in the numbers or on the hands and you
still can't come down with the ball, people start saying, "Hmm. You know, this guy is 32 years old. Maybe we should find another quick slot guy?"
Finally, as a little side-note, both the Redskins and the Colts have more to fight for this weekend than do the Patriots.
Anyways, roll with Reggie Wayne and Pierre Garçon. Good luck!