Preheat oven to 400° F and line a baking sheet with foil. Spread out sweet potatoes and drizzle with 1 tbsp olive oil, salt and pepper. Bake for 20 minutes, tossing once halfway through. Reduce oven temperature to 350°F.

Heat a large skillet over medium heat. Add turkey and cook until browned, using a spatula to chop into small pieces. Add onion and garlic and cook until softened, about 4 minutes. Stir in black beans, sweet potato, and 1/2 cup of enchilada sauce; remove from heat.

Spray a 9x13 inch baking dish with non-stick spray and coat bottom of pan with 1/4 cup enchilada sauce.

Add a generous scoop of filling to each tortilla. Roll up and place seam-side down in baking dish, repeating until all tortillas are filled. (If you have any leftover filling, you can spoon it over enchiladas or fill in the sides of the pan.)

Pour remaining enchilada sauce evenly over top. Top with cheese and bake at 350° F for 20 to 25 minutes, until cheese is golden and bubbly.

While the enchiladas are cooking, prepare the avocado sauce by combining avocado, yogurt, lime, cilantro, and 1/4 cup water in a food processor or blender. Blend until creamy, and season to taste with salt and pepper. If sauce is too thick, add extra water or lime juice as needed.

Once enchiladas are cooked, drizzle sauce overtop. Top with extra cilantro and/or green onion, if desired.