Preheat oven to 375°F (190°C). Grease a 9×13-inch baking dish. In a pan over medium heat, melt butter and whisk in flour. Cook for 1 minute. Gradually whisk in chicken broth and green enchilada sauce, stirring until thickened. Stir in sour cream, green chilies, garlic powder, onion powder, cumin, salt, and black pepper. In a bowl, combine shredded chicken with 1/2 cup shredded cheese. Divide the chicken mixture among tortillas, roll them up, and place them seam-side down in the baking dish. Pour the sauce evenly over the enchiladas and sprinkle the remaining cheese on top. Bake for 20 minutes until cheese is melted and bubbly. Garnish with chopped cilantro or diced tomatoes if desired. Serve warm.
Notes
For extra spice, add a dash of cayenne pepper or top with jalapeños before baking