Cook the Sweet Potato: If you haven't already, bake or microwave your sweet potato until tender, about 8 to 10 minutes in the microwave or 45 minutes in a 400°F oven. Let it cool, then peel and dice into 1/2-inch cubes.
Combine Filling: In a large bowl, mix the diced sweet potato, corn and black bean salsa, and 1 cup of the shredded cheese until evenly combined. This mixture should be moist but not wet.
Taste and Adjust: Season with salt and pepper to taste, and consider a pinch of cumin or paprika if you'd like extra warmth and depth.
Prepare the Baking Dish: Preheat your oven to 350°F and spread a thin layer of enchilada sauce across the bottom of a 9x13-inch baking dish.
Fill and Roll: Warm each tortilla slightly to make it pliable, then fill with about 3 to 4 tablespoons of the sweet potato mixture. Roll tightly and place seam-side down in the prepared baking dish, nestling them close together.
Cover with Sauce and Cheese: Pour the remaining enchilada sauce evenly over the rolled enchiladas, then sprinkle the remaining 1 to 1 1/2 cups cheese on top.
Bake: Cover with foil and bake for 20 to 25 minutes until heated through, then remove the foil and bake for another 5 to 8 minutes until the cheese is melted and lightly golden.