Preheat the oven to 400°F and lightly grease a 9x13 baking dish.
Toss the sweet potato cubes with 1 tablespoon olive oil, cumin, chili powder, and salt. Spread them on a baking sheet and roast for 20 minutes until tender.
While the sweet potatoes roast, heat the remaining tablespoon of olive oil in a skillet over medium heat. Add the onion and garlic and cook until softened, about 3 minutes.
In a mixing bowl, combine the roasted sweet potatoes, cooked onion and garlic, and black beans. Stir gently to mix.
Warm the tortillas briefly so they do not crack. Spoon the filling into each tortilla, roll them up, and place them seam-side down in the baking dish.
Pour the enchilada sauce evenly over the rolled tortillas and sprinkle the shredded cheddar cheese on top.
Bake for 20 minutes until the cheese is melted and the edges are bubbly. Let the dish rest for 5 minutes before serving.