Boil Chicken breasts in pot approx. 35 -40 mins. Or until done. When done, cool in frig or freezer, until you can touch.
Soften tortillas in hot oil in shallow pan, one at a time, draining on paper towels
Saute onion and bell pepper in hot oil till soft, 10 mins. Or so.
Mix onion, bell pepper, crm.of mushroom, crm.of chicken, sour cream , garlic and chili powder in large bowl.
Shread or chop chicken and add to bowl.
Fill tortillas with approx. 3 T. chicken filling and approx. 1 T. of cheese, roll and place in a greased or sprayed 9 x 11 glass baking dish. Usually makes more than will fit in dish, use another dish.
Cover all enchiladas in pan(s) completely with left over chicken filling (should be approx 2 cups left), and remainder of cheese.
Cover with Foil and Bake at 375 degrees for 45 minutes