Preheat the oven to 400°F (200°C). Pierce the sweet potatoes with a fork and place them on a baking sheet. Bake for 45-60 minutes, or until tender.
While the sweet potatoes are baking, heat olive oil in a large skillet over medium heat. Add the diced onion and sauté for 3-4 minutes until softened.
Add the minced garlic to the skillet and cook for an additional minute until fragrant.
Stir in the ground turkey, chili powder, cumin, paprika, salt, and pepper. Cook until the turkey is browned and cooked through, about 6-8 minutes.
Add the black beans and corn to the skillet, mixing well. Cook for another 2-3 minutes until heated through.
Once the sweet potatoes are done, remove them from the oven and let them cool slightly. Cut them in half lengthwise and scoop out a small portion of the flesh to create space for the filling.
Fill each sweet potato half with the turkey mixture, then top with shredded cheddar cheese. Return to the oven for 5-10 minutes until the cheese is melted.
Remove from the oven and garnish with fresh cilantro and a dollop of sour cream or Greek yogurt if desired.