Can you expand further on your requirements.

Do you have the NetBackup Vault product add on. If so consult the guides for it. If not then this is the introduction paragraph for the product which might help you decide if this is for you.

Vault is an extension to NetBackup that automates selection and duplication of
backup images and ejection of media for transfer to and from a separate, off-site
storage facility. NetBackup Vault also generates reports to track the location
and content of the media. Vault functionality does not have to be used only for
disaster recovery; you can use Vault to manage data and media that you store
off-site for regulatory archival purposes.

You have to pay extra for this extension.

Listing of all NB Guides incl Vault  - http://seer.entsupport.symantec.com/docs/290282.htm

Alternative - some admins use scripts using the netbackup commands to control what is to be ejected from a previous backup cycle or period. And thereafter manually manage vaulting practices.

A lot of people by Vault to handle it.

I don't, Not big enough here.

So that leaves you with the manual process.

1) run the media written report starting from the time you nightly backups run to current.
eject any tapes that were written to.

2) much easier  for me - go to media and sort by time assigned and Robot control  This will bring all the tapes that were recently written to to the top of your list.
Highlight all tape with time assigned ( watch out for any that may be in for restores) and eject them