In a large skillet, heat the vegetable oil over medium heat. Add the chopped onion and sauté until translucent, about 3-4 minutes. Stir in the minced garlic and cook for an additional 1 minute until fragrant.

Add the rice to the skillet and toast it for about 2-3 minutes, stirring frequently, until it turns a light golden color.

Pour in the chicken broth and add the diced tomatoes with their juices, cumin, chili powder, salt, and black pepper. Stir to combine.

Bring the mixture to a boil, then reduce the heat to low. Cover the skillet and let it simmer for 18-20 minutes, or until the rice is tender and the liquid is absorbed.

If using, stir in the frozen peas during the last 5 minutes of cooking. Remove from heat and let it sit, covered, for an additional 5 minutes.

Fluff the rice with a fork and garnish with chopped cilantro before serving.