In a large skillet over medium heat, add the olive oil. Once hot, sprinkle in the all-purpose flour and chili powder. Stir continuously for about 1-2 minutes until the mixture is well combined and fragrant.
Slowly whisk in the tomato sauce and vegetable stock until smooth. Continue to stir and let the sauce simmer for about 5 minutes.
Add the garlic powder, onion powder, cumin, and season with salt and pepper to taste. Let the sauce simmer for an additional 5 minutes.
In a medium bowl, combine the cooked and diced chicken with a generous amount of the prepared sauce. Mix well to ensure the chicken is coated.
Preheat your oven to 350°F (175°C). Spread a thin layer of the sauce on the bottom of a baking dish. Take a tortilla and spoon a generous amount of the chicken mixture onto the center. Sprinkle with a handful of shredded Colby Jack cheese, then roll the tortilla tightly around the filling.
Once all the enchiladas are in the baking dish, pour the remaining sauce over the top and sprinkle the remaining cheese. Bake for about 20-25 minutes, or until the cheese is bubbly and golden.
Remove the enchiladas from the oven and let them cool for a few minutes before serving. Garnish with fresh cilantro, diced avocado, or a dollop of sour cream if desired.
