Reduce heat to medium-low. Add the remaining 2 tablespoons oil, then add the onion and carrots to the pot and season with salt and pepper. Cook, stirring occasionally, until softened, 5 minutes. Add tomato paste and garlic, and cook, stirring occasionally, until tomato paste is lightly caramelized, about 3 minutes. Stir in chili powder, cumin, and oregano until well blended.