Preheat oven to 375 degrees F. Coat a 9×9 casserole dish with cooking spray.
Cook the turkey in a medium skillet and season with chili powder, salt, and pepper. Remove from heat. Place thinly sliced sweet potatoes on the bottom of the 9×9 pan. Top with turkey, spinach, and onion.
In a large bowl, whisk 10 eggs together and season with salt and pepper. Pour eggs over veggie and turkey mixture. Bake for 40-45 minutes until sweet potatoes are soft and eggs are cooked through.