The easiest way to export NSF emails to PST format is to utilize ZOOK NSF to PST Converter, which is the most efficient solution available. It allows users to export many emails at once, complete with attachments. All IBM Lotus Notes, including Notes 9.0.1/9.0/8.5/8.0, and so on, are supported. Even after the conversion procedure, NSF to Outlook Converter maintains all of the email attributes and data integrity. There's also a FREE TRIAL EDITION available for the same. 

Check for more details at: Export NSF Files into PST Format