Sauté the chicken, mushrooms, onion, green chilies, and spices in the butter over medium heat until the chicken is cooked.
Remove from heat and stir in ½ the cheese.
In a saucepot melt the butter and add the flour.
Cook over medium heat for about 4 minutes while stirring with a whisk.
Add the chilies milk and chicken stock and whisk until it comes to a full boil and thickens.
Simmer for about 10 minutes.
Remove from heat and add the sour cream and the other ½ cup of cheese.
Put the layer of sauce in a baking dish, and then roll the quesadilla filling the tortillas and place over the sauce.
Pour the rest of the sauce over the enchiladas and bake at 350 degrees until hot and bubbling.
Garnish with sour cream, salsa, and avocado.