Preheat oven to 350 degrees Fahrenheit. In a medium-sized skillet, add the ¼ cup olive oil, 2 tablespoons all-purpose flour, and 3 tablespoons chili powder. Whisk until it starts to brown and is fragrant.
Slowly whisk in the 1 (15-ounce) can tomato sauce, 1 ½ cups vegetable stock, ½ teaspoon garlic powder, ½ teaspoon onion powder, and ¼ teaspoon cumin, and salt and pepper to taste. Whisk until it starts to thicken.
Reserve 1 ½ cups of the sauce. Add the 2 cups cooked and diced chicken to the rest of the sauce.
To assemble, add about 2 tablespoons of 3 cups shredded Colby Jack cheese and some of the chicken sauce to the center of each of the 8-10 flour or corn tortillas.
Roll up the filled tortillas and place seam side down in a 9x13 inch baking dish. Repeat.
Top with the reserved sauce and sprinkle the top with remaining cheese. Bake for 20-25 minutes or until heated through and bubbly.