Preheat oven to 375°F (190°C). Grease a 12-cup muffin tin.
In a large bowl, combine the shredded chicken, enchilada sauce, half of the cheddar cheese, Monterey Jack cheese, drained diced tomatoes, sour cream, chopped cilantro, chili powder, cumin, garlic powder, salt, and pepper. Stir well to combine.
Spoon the mixture evenly into the prepared muffin cups, filling each about two-thirds full.
Bake for 20-25 minutes, or until heated through and lightly golden on top. Sprinkle with the remaining cheddar cheese during the last 5 minutes of baking.
Let cool slightly before removing from the muffin tin. Serve warm.
Notes
Serve with your favorite enchilada toppings like avocado, salsa, or extra sour cream!