Preheat oven to 400 degrees F.
Wrap corn tortillas in wet paper towels and microwave for 45 seconds. In a large bowl, combine chicken, 1 1/2 bags of cheese, onion, cilantro, and 2 cans of enchilada sauce. Mix well Add the cilantro and stir to combine.
Cover the bottom of a large baking dish with half of the remaining enchilada sauce.
Carefully spoon mixture into tortillas, roll up and place seam side down in the baking dish. Cover the top with the other half can of the enchilada sauce and the rest of the cheese (1 1/2 bags). Bake for 35 to 40 minutes. Serve with sour cream sauce.
Make sour cream sauce by adding butter to a saucepan over medium heat. While the butter is melting add the chicken broth, cumin, garlic and sour cream. Whisk to combine; season with salt, bring to a boil and remove from the heat.
Serve enchiladas topped with sour cream sauce.