The best way to export NSF files from Lotus Notes suggested by me and also technical expertise will be SysInspire NSF to PST converter tool.
This tool can extract the contents and get it arranged in a structured configuration and then export the NSF file from the Lotus Notes. The internal structure remains the same in the original form and mostly, there is no need for Outlook launched on your PC. Each email after the export is captured with all the properties like the cc, bcc, subject, message etc.
If you wish to know about how to export NSF files from Lotus Notes, then I will recommend you to download the SysInspire NSF to PST converter. This has become the most reliable software and it makes sure there are no further issues found after the export of the NSF files. When I downloaded the application I had to open the file, then I scanned my file and checked its contents then to verify whether this is the same file. Then I went for the final export of the Nsf file.