Yes, you can cook frozen diced potatoes in an air fryer if you don't have fresh potatoes.  Preheat the air fryer, toss the frozen diced potatoes in a bit of oil and seasoning, then spread them in a single layer in the air fryer basket. Cook at 400 degrees for about 15-25 minutes, shaking or stirring halfway through to ensure even cooking. Cooking times may vary based on the air fryer model, so adjust to your cooking time as needed.