Hi @williamcra81956
If you don't get a better answer, here's the [document|42063|parts list] that may give an idea of what to do.
In Fig.4 on p.5 it shows the SD card cover (part #1F999-551) and the SD card lid (part #1F999-552) and how they fit into the camera.
Search online for [https://www.google.com/search?client=firefox-b-d&q=Nikon+1F999-552|Nikon 1F999-552] to find suppliers that suit you best. (supplier examples only)