Add the vegetable oil to a sauce pan. Once heated, stir in the flour and cook for a couple of minutes until it forms a smooth paste. Add the chili powder, ground cumin, garlic powder, and dried oregano. Stir well to combine the spices with the flour mixture. Pour in the chicken or vegetable broth, stirring constantly to avoid lumps. Bring the sauce to a simmer and let it cook for about 10 minutes until it thickens to your desired consistency. Season with salt and pepper to taste. Set the sauce aside.