Preheat the oven to 375°F. Spread about 1/2 cup of the enchilada sauce across the bottom of a 9x13 inch baking dish to prevent sticking.
In a large bowl, combine the shredded chicken, sour cream, cream cheese, diced green chiles, 1 cup of the shredded cheese, cumin, and garlic powder. Season with salt and pepper and mix until everything is well combined and creamy.
Warm the corn tortillas briefly in the microwave, wrapped in a damp paper towel, for about 30 seconds to make them pliable. This prevents them from cracking when rolled.
Spoon about 1/3 cup of the chicken filling down the center of each tortilla, roll it up tightly, and place it seam-side down in the prepared baking dish. Repeat until all tortillas are filled and lined up snugly in the dish.
Pour the remaining enchilada sauce evenly over the rolled tortillas, making sure to coat the edges. Sprinkle the remaining 1 cup of cheese over the top.
Cover the dish with foil and bake for 20 minutes. Remove the foil and continue baking for another 10 minutes, until the cheese is melted and bubbly and the edges are slightly golden. Top with fresh cilantro and sliced jalapenos if desired, and serve hot.