Heat the avocado oil in a small saucepan over medium heat. Add the flour and whisk for 1 minute. Add the chili powder, cumin, garlic powder, salt, and oregano and whisk for 1 minute. Slowly add the tomato sauce and then the broth, whisking continuously until smooth.
Simmer for 12 minutes, or until thickened. The sauce will thicken more as it cools. Use in your favorite enchilada recipe.