NK2Reader is a reader of Outlook autocomplete streams (nk2 files).
Add the following line to your project's SwiftPM dependencies:
.package(url: "https://github.com/hughbe/NK2Reader", from: "1.0.0"),import NK2Reader
let data = Data(contentsOfFile: "<path-to-file>.nk2")!
let file = try NK2File(data: data)
for row in files.rows {
print(row.displayName!)
}