Heat the olive oil in a large skillet over medium heat. Add the onion and garlic and cook for 3 minutes. Add the bell pepper and black beans and cook for an additional 5 minutes.
Add the cooked rice to the skillet and stir to combine. Pour the enchilada sauce over the top of the mixture, stirring to combine.
Stir in the diced green chiles and cook until everything is heated through. Serve with your favorite toppings.