You can add chicken or steak to the sheet pan, but will need to make sure they are added at the right time to ensure enough cooking time. For chicken cut into 1-2 inch pieces, you will need to cook it for about 20 minutes until it reaches 165 F internal temperature. You can add it to the pan separated from the potatoes right at the start. Just check to ensure that it doesn't overcook as you get close to 30 minutes. Check out my recipe for adding a Flank Steak to the sheet pan!