MBOX file is a simple mail message that supports various online and portable email clients such as Gmail, WebMail, Thunderbird, Netscape, Entourage, SeaMonkey, Apple Mail, etc. To convert MBOX to PST format, the user can use MailsDaddy MBOX to PST converter tool. This GUI tool has several other features that allow users to convert single or multiple email clients' data to Windows Outlook. It preserves all data folders, inline images, attachments, and other mail stuff during the whole migration. The application comes with the free demo version that exports 20 emails from each mailbox. For more detail: MBOX to PST Converter
If you want to know the correct method of convert MBOX to NSF file, try eSoftTools MBOX Converter Software, this tool provides best features for conversion because there is no direct method to convert MBOX to NSF files. This tool is the right and easy way to convert several MBOX files into NSF at one time without limitations. And it is compatible with all versions of Windows O/S, including win- 10,8.1,8,7, XP, and many more.