Preheat your oven to 400°F (200°C).
Wash the sweet potatoes thoroughly and pierce them several times with a fork. Place them on a baking sheet and bake for 45-60 minutes, or until tender.
While the sweet potatoes are baking, heat olive oil in a skillet over medium heat. Add chili powder, cumin, garlic powder, smoked paprika, salt, and pepper. Stir for about 1 minute until fragrant.
Add black beans, corn, and diced tomatoes to the skillet. Cook for 5-7 minutes, stirring occasionally, until heated through.
Once the sweet potatoes are done, remove them from the oven and let them cool slightly. Cut each sweet potato in half lengthwise and scoop out a small portion of the flesh to create a boat.
Fill each sweet potato half with the black bean mixture, then top with shredded cheddar cheese.
Return the stuffed sweet potatoes to the oven and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Remove from the oven and garnish with chopped cilantro and diced avocado. Serve with lime wedges on the side.