Place chicken breasts, 1.5 cups of enchilada sauce, green chiles, onion, garlic powder, cumin, salt, and pepper into a slow cooker.
Secure the lid and cook on high for 4 hours or low for 8 hours until the internal temperature reaches 165 degrees Fahrenheit.
Remove the chicken to a clean work surface and shred using two forks, then return the shredded meat to the slow cooker to incorporate with the sauce.
Lay out tortillas and distribute the chicken mixture evenly among them, adding a tablespoon of cheese to each before rolling tightly.
Layer the rolled tortillas in the slow cooker or a baking dish, topping with the remaining sauce and cheese.
Heat on high for an additional 20-30 minutes until the cheese is fully melted and the edges are bubbling.
Garnish with fresh cilantro and serve immediately.