Import NSF files to Office 365 using Migration Tool for conversion. To import NSF files to your Office 365 account, use a third-party converter tool or Microsoft Outlook. To import NSF files to an Office 365 account, use a professional migration tool or convert the NSF files to PST format, then import them. https://www.vartikasoftware.com/product/vs-nsf-to-office365-converter.html