01 - Preheat oven to 350°F. Lightly grease a 9x13-inch baking dish.
02 - In a mixing bowl, blend shredded chicken, 1 cup Monterey Jack cheese, 1/2 cup sour cream, green onions, garlic powder, cumin, salt, and black pepper until well combined.
03 - Melt butter in a saucepan over medium heat. Add flour and cook, stirring, for 1 to 2 minutes until mixture bubbles without browning.
04 - Gradually whisk in chicken broth. Continue stirring until slightly thickened, about 3 minutes.
05 - Remove sauce from heat. Whisk in sour cream, green chilies, onion powder, and salt until smooth and fully combined.
06 - Distribute chicken filling evenly among tortillas. Roll up each tortilla and arrange seam-side down in the prepared baking dish.
07 - Pour white sauce evenly over filled tortillas. Sprinkle with remaining cup of Monterey Jack cheese.
08 - Bake uncovered for 25 to 30 minutes, or until cheese is bubbling and the top is lightly golden.
09 - Allow to cool briefly. Garnish enchiladas with chopped cilantro and extra green onions before serving.