Place the lid on the Ninja Foodi set the valve to sealing and pressure cook for 0 minutes. Do a quick pressure release and remove the liquid from below the air fryer basket.
Place the air fryer lid down on the Ninja Foodi and cook for 20 minutes at 200c/400f. Halfway through shake the roast potatoes (for an even cook) and if they are not getting crispy fast enough add some extra virgin olive oil spray.