Melt butter in a large skillet over medium heat; cook and stir onion until tender (about 5 min).
Mix together the following: chicken soup, sour cream, cumin, cream cheese, milk.
Blend together until smooth . . . add the shredded chicken and the green chilies.
In a greased pan, place a single layer of the tortillas in the bottom of your pan.
Then a layer of the chicken mixture
Then some cheese . . . more tortillas, chicken mixture and cheese . . .
If you have enough for three layers . . . then repeat.
Top layer is the cheese. (sprinkle with some jalapenos if you would like)
Bake 350º until heated through and cheese is melted. Cut into squares . . .