Place the sliced sausage, peppers, and onions in a big mixing bowl.
Pour in the oil and sprinkle all the seasonings over the ingredients.
Use tongs or spoons to mix everything well until all pieces are nicely coated.
Transfer the mixture into your air fryer basket; work in batches if needed so it’s not piled too high.
Set the air fryer to 400°F and cook for 12 minutes, shaking or stirring the contents halfway through the cooking.
If you want extra crispness, continue cooking for an additional 2 minutes.
Carefully remove from the air fryer and add more salt, pepper, or garlic powder if you like before serving.