I will have shorts or a robe on if I'm expecting the delivery such as food. If I'm not expecting a delivery, I will usually crack open the door and ask them to wait a minute while I go put a robe on...my robe for this purpose is by the back door as I usually put it on to go outside and around the corner of the house that is visible to neighbors. Now, if it is NOT a delivery, then I will answer the door in my natural state and partially visible to the person...enough for them to be aware that I'm nude and decide how they want to proceed with their business. Anyone who then wants to engage with me IN MY HOME will be doing so while I'm nude. That's their choice.
Unfortunately, in this day and age of porch pirates all the delivery drivers take pictures of the package either on the porch after they deliver it, or of it being delivered to your hands. That most likely means they are going to have a picture midsection if you answer the door nude. These pictures are then downloaded to the servers of the delivery company. What happens to them after that who knows