Dice onion and saute with butter. Set aside. Cook chicken. Meanwhile, add sour cream, cream of mushroom soup, salt, pepper and onion/butter mixture together in a small bowl. Stir. Dice cooked chicken. Place some of the sour cream mixture in the middle of a tortilla. Add chicken on top. Roll tortilla. Repeat until your 8 X 10 pan is full (holds 8). Spread remaining sour cream mixture on top. Sprinkle cheese over all. Cover with tin foil and place in a 375 degree oven for 30 minutes. Remove foil from top and cook for 15 more minutes. Enjoy!
Notes
I just put "some" of the mixture in each tortilla. Just make sure you have enough for all 8. If you run out of the sour cream/soup mixture - just add more sour cream to cover each tortilla.Adapted from From my mom!