You can take a snapshot of the NSX Manager VM, and revert to snapshot if needed. It is also recommended to configure backups of NSX Manager. In the event of failure or need to roll back, you can deploy a new NSX Manager VM on the same IP, and restore from the backup. The rollback of other components involve other tasks. Controller rollback requires a call to support.
The document below does a very thorough job of detailing the backup and restore procedures for the various NSX components.
NSX-v Operations Guide, v6.1
