Heat oven to 350 degrees F. Lightly grease a large baking dish.
In a medium pan over medium heat, melt the butter and sauté the
green onion until tender. Add the garlic powder, then stir in the
green chiles, cream of mushroom soup and sour cream; mix well. Reserve
3/4 of this sauce and set aside.
To the remaining 1/4 of the sauce in the saucepan add the chicken
and 1/2 cup shredded Cheddar cheese. Stir together.
Fill each flour tortilla with the chicken mixture and roll up. Place
seam side down in the prepared baking dish.
In a small bowl, combine the reserved 3/4 of the sauce with the
milk. Spoon this mixture over the rolled tortillas and top with
the remaining 1/2 cup shredded Cheddar cheese.
Bake for 30 to 35 minutes or until cheese is bubbly.