Thinly slice the sweet potatoes, then rinse them in cold water and pat dry.
Preheat Ninja Foodie at 400 degrees Fahrenheit for 5 minutes.
Evenly spread the sliced sweet potato out on the cook and crisp plate, sprinkle with cinnamon.
Cook for 3 minutes, reduce to 300 degrees Fahrenheit and cook for another 5 minutes.
Allow to cool before serving.