Chicken and spinach curry (recipe is actually for turkey, but chicken works fine):
http://www.nytimes.com/2009/11/25/dining/251mrex.html?_r=0
Butter chicken (the recipe I have calls for pre-cooked chicken though some recipes call for it raw)
Chicken fried rice.
Chicken pot pie (we make ahead and then just bake on the night of dinner, but it does take a little longer than 20 minutes)
White chili
Quiche (bake ahead)
I often chop up leftover chicken and throw into pasta sauces, rice dishes, etc.