Preheat the oven to 375 degrees and lightly grease a 9x13 baking dish.
Heat the olive oil in a large skillet over medium heat. Add the onion, garlic, and red bell pepper. Cook for 5 minutes until the vegetables begin to soften.
Stir in the cumin, chili powder, salt, and black pepper. Cook for 1 minute until the spices are fragrant.
Add the cubed sweet potatoes, black beans, and diced tomatoes with their juices to the skillet. Stir everything together and let it cook for 3 minutes.
Transfer the mixture to the prepared baking dish and spread it into an even layer.
Sprinkle the shredded cheddar cheese evenly over the top.
Cover the dish with foil and bake for 25 minutes. Remove the foil and bake for another 10 minutes until the cheese is melted and the sweet potatoes are tender.
Remove from the oven and let it rest for 5 minutes before serving. Garnish with fresh cilantro.