In a large pot, heat oil over medium heat. Add onions and sauté until soft and translucent, about 2-3 minutes.
Add chili powder, onion powder, garlic powder, cumin, salt, pepper, and oregano and sauté until spices are fragrant and golden, about 1-2 minutes more.
Add tomatoes, black beans, lentils, corn, and broth, and stir. Bring to a boil, reduce the heat to low, cover, and simmer for 15 minutes. Do not add the rice at this step. This allows the lentils to begin cooking first.
Add rice, stir, cover and simmer for 20 minutes or until the rice is cooked through and tender.
Fluff the rice, spoon into bowls, and top with cheese, Greek yogurt or sour cream, and avocado. Enjoy!