I think he can honestly win the chamber. In all likelihood the chamber will have Sheamus, Trips, Morrison, Miz, Wade, and 1 other person. I'm not sure if the other person will be Randy or Cena because I can honestly see them letting one of them win the rumble again like Austin and HBK did (Cena has the stronger chance).
They can book his way into winning the match easily if they go with Trips beating Sheamus, and then have Sheamus attack him afterward and cause him to get eliminated. From there you do the big missed chamber spot (Morrison) elimination. Then you see whoever the last guy is get double teamed by the heels only to make a heroic comeback to even the odds, and then Miz eliminates the hero at the end.
I see them booking Miz vs Cena at Mania and having their whole initial feud when Miz came to Raw come full circle.