Preheat your oven to 375°F (190°C).
In a skillet, heat the vegetable oil over medium heat.
Add the chopped onion and sauté for about 4-5 minutes until translucent.
Stir in the minced garlic, cumin, and chili powder, cooking for another minute.
Combine the cooked chicken with the sautéed mixture and mix well.
Spread a thin layer of enchilada sauce on the bottom of a baking dish.
Fill each tortilla with the chicken mixture, roll tightly, and place seam-side down in the dish.
Pour the remaining enchilada sauce over the rolled tortillas, ensuring even coverage.
Sprinkle the shredded Monterey Jack cheese over the top.
Bake in the preheated oven for 20-25 minutes, or until the cheese is bubbly and golden.
Let the enchiladas cool for a few minutes before serving.
