Using a sharp knife and a cutting board, dice chicken into 1/2 inch pieces. Also, dice onion finely.
In a large skillet, heat 2 tablespoons of olive oil over medium-high heat. Once the oil is shimmering, add the chicken, onion, 1 teaspoon of salt, 1/2 teaspoon of black pepper, and chicken base. Cook until the chicken is browned on the outside, but not cooked all the way through.
With the spatula, move the chicken to one side of the pan. In the empty side of the pan, add the remaining 1 tablespoon of olive oil. Add the uncooked rice on top of the oil, and saute for 3-5 minutes until the rice grains begin to brown and smell nutty.
Add the tomatoes, black beans, garlic powder, chili powder, cumin, and water, and stir everything together. Bring the mixture to a simmer, and reduce the heat to low.
Cover the skillet, and cook the mixture until the rice is tender, about 20 minutes.
Remove the skillet from the heat, and sprinkle the cheese on top of the mixture. Cover the skillet once more, and let the mixture sit for 2-3 minutes to melt the cheese.
Portion into individual bowls, and top with any of the optional ingredients, and serve!