Answering three years later for posterity -
Rather than providing the zipped contents, provide a URL to the folder itself. Here's the basic idea:
						let folderUrl = ...
						let itemProvider = NSItemProvider()
						itemProvider.suggestedName = folderUrl.lastPathComponent
						itemProvider.registerFileRepresentation(forTypeIdentifier: "public.folder", visibility: .all) {
								$0(folderUrl, false, nil) // wild stab in the dark for mysterious undocumented boolean
								return nil
						}