To open the NSF file in Outlook, download the SysInspire NSF to PST converter.
Open the third party application.
Click on the File option and then select Open followed by the Import option
An import and Export wizard will open up on the screen.
Choose an export option and then, click Next
From the next window, click on Browse to select the NSF file.
Select the destination location where you have to save the resultant PST file.
At last, click on Finish
The export of the NSF files will start.
Then you can check out your lotus notes in Outlook. In case the file is large enough, then go for the pst split option to make small-sized pst files.
Also, you can go for the date filtration option.
More info:- Open NSF files in outlook