Melt the butter with the vegetable oil in a saucepan over medium heat.
Add the all-purpose flour and whisk until completely smooth. Cook briefly, stirring constantly, to remove the raw flour taste.
Add the chili powder and paprika. Whisk them into the roux and cook briefly, just until fragrant and evenly combined.
Stir in the tomato paste until well blended.
Add the onion powder, garlic powder, ground cumin, and oregano. Stir until the seasonings are evenly incorporated.
Gradually pour in the chicken stock while whisking continuously to keep the sauce smooth and prevent lumps.
Bring the sauce to a gentle simmer. Cook, whisking occasionally, until smooth, glossy, and lightly thickened while still remaining easily pourable.
Stir in the sugar. Taste the sauce and add salt only if needed, depending on how salty your chicken stock is.
Remove from the heat and use right away, or let the sauce cool before storing. Keep in mind that the sauce will thicken slightly as it cools.