01 - Preheat the oven to 350°F (175°C). Lightly grease a 9x13-inch baking dish and set aside.
02 - In a large mixing bowl, blend the shredded chicken with 1 cup Monterey Jack cheese, 1/2 cup sour cream, green onions, garlic powder, cumin, salt, and black pepper until thoroughly combined.
03 - In a saucepan over medium heat, melt the butter. Sprinkle in flour and stir constantly for 1–2 minutes, allowing it to bubble without browning.
04 - Gradually whisk in the chicken broth, ensuring a smooth consistency. Continue stirring and cook until the mixture thickens slightly, about 3 minutes.
05 - Remove the saucepan from heat, then whisk in sour cream, diced green chilies, onion powder, and salt until the sauce is velvety and smooth.
06 - Distribute the chicken filling evenly among the flour tortillas. Roll each tortilla tightly and position seam-side down in the prepared baking dish.
07 - Pour the warm white sauce over the filled tortillas, ensuring all are well coated. Sprinkle evenly with the remaining 1 cup Monterey Jack cheese.
08 - Bake uncovered in the preheated oven for 25–30 minutes, or until the enchiladas are bubbly and lightly golden on top.
09 - Allow to rest briefly before serving. Finish with chopped cilantro and additional green onions for a fresh presentation.