In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add 1 diced yellow onion and sauté for about 5 minutes, or until it turns translucent. Stir in 2 minced garlic cloves and cook for an additional minute until fragrant.

Add 2 cups of cooked shredded chicken to the skillet along with ½ cup of mild red enchilada sauce, 1 teaspoon chili powder, 1 teaspoon ground cumin, and 1 teaspoon dried oregano. Cook for 5-7 minutes until heated through.

Once the filling has cooled slightly, gently stir in 1 cup of shredded Monterey Jack cheese until well combined.

Warm the large flour tortillas in the microwave or a skillet for 20-30 seconds until they are pliable.

Take each warmed tortilla and place about ½ cup of the chicken and cheese filling in the lower third. Fold the sides inward and roll them up tightly.

Preheat your oven to 400°F (200°C) and prepare a baking sheet by lightly coating it with cooking spray.

Place the assembled chimichangas seam-side down on the prepared baking sheet. Spray the tops with cooking spray and bake for 15-20 minutes until golden brown.

Remove from the oven, carefully take out any toothpicks, and serve hot with your favorite salsa, sour cream, or guacamole.