Divide tomatillos, onion, jalapeño & garlic onto 2 baking sheets. Drizzle with olive oil and sprinkle with salt & pepper. Roast 30 minutes at 425F. Place roasted veggies, cilantro, lime juice and salt in a blender and pulse until you have a sauce.
Place diced sweet potatoes on a baking sheet, drizzle with olive oil, sprinkle with salt & pepper, cumin and paprika. Roast for 30 minutes. Roughly chop some of the roasted onion and place in a bowl with roasted sweet potatoes and black beans.
Dip tortillas in the tomatillo sauce and fill with sweet potato mixture. Roll and place in a baking dish. Add remaining sauce over the top. Top with cheese and bake for about 30 minutes at 375F.