Preheat the oven to 400 degrees Fahrenheit.
Add the shredded chicken, enchilada sauce, black beans, and corn to a large mixing bowl. Gently stir to combine. Season with salt and pepper, to taste. Set aside.
Lightly spray a 9 x 13 inch casserole dish with cooking spray. Add the spiralized sweet potatoes. Then, pour the shredded chicken mixture over the sweet potatoes and top with shredded cheese. Cover tightly with aluminum foil.
Bake in the preheated oven for 50 minutes to 1 hour, until the cheese is bubbly and the sweet potatoes are cooked through. Remove the aluminum foil for the last 10 minutes of cooking.
Allow the casserole to rest a few minutes before serving. Top with green onions, avocado, parsley, and sour cream.