A backup can be expired with the following command:
.\nvexpiresaveset.exe -savesetid ###
If there's a duplicate of the backup, it can also be removed by adding the -duplicates flag:
.\nvexpiresaveset.exe -duplicates -savesetid ###
A way to list the IDs from the backups is through "nvrestore -list", however it may return more information than needed so the output may need to be filtered:
\nvrestore.exe -list | findstr NVDB
WIN-FOUN68OF85G NetVault Databases NVDB-2-RPRADOQS (Saveset 132) 14:28 11 Jul 2019
WIN-FOUN68OF85G NetVault Databases NVDB w/Duplicate (Saveset 117) 13:29 13 Mar 2019
WIN-FOUN68OF85G NetVault Databases NVDB w/Duplicate (Saveset 116) 13:22 13 Mar 2019
WIN-FOUN68OF85G NetVault Databases NVDB w/Duplicate (Saveset 115) 12:59 13 Mar 2019
WIN-FOUN68OF85G NetVault Databases NVDB w/Duplicate (Saveset 114) 12:12 13 Mar 2019
With the above details a script can be created to delete multiple savesets.