Toast the Rice: Heat the oil in a large skillet over medium heat. Add the rice and stir frequently until it starts to turn golden brown, about 3-5 minutes.
Add Vegetables: Add the chopped onion and bell pepper to the skillet. Cook until the vegetables are soft, about 3-4 minutes. Add the minced garlic and cook for another 30 seconds.
Add Tomato Sauce and Spices: Stir in the tomato sauce, chicken broth, cumin, and chili powder (if using). Add salt and pepper to taste.
Simmer the Rice: Bring the mixture to a boil, then reduce the heat to low. Cover the skillet with a tight-fitting lid and let it simmer for about 18-20 minutes, or until the rice is tender and the liquid is absorbed.
Finish and Serve: If desired, stir in the frozen peas during the last 5 minutes of cooking to warm them through. Once the rice is cooked, fluff it with a fork. Garnish with fresh cilantro if desired.