Preheat your oven to 375°F (190°C).

In a large skillet, heat olive oil over medium heat and cook the chopped onion until translucent, about 5 minutes.

Add shredded cooked chicken, cumin, garlic powder, salt, and pepper to the skillet. Stir well to combine and cook for an additional 5 minutes.

Spread a thin layer of enchilada sauce on the bottom of a baking dish.

Warm the tortillas in the microwave for about 30 seconds to make them pliable.

Fill each tortilla with the chicken mixture and some shredded cheese. Roll them up and place seam-side down in the baking dish.

Pour the remaining enchilada sauce over the top of the rolled tortillas and sprinkle with the remaining cheese.

Bake in the preheated oven for 20-25 minutes, or until the cheese is melted and bubbly.

Serve hot, garnished with chopped fresh cilantro, sour cream, or avocado slices if desired.