Within Notezilla , it is not possible to switch to different users. But there is an easy way.
You can download the portable version of Notezilla and run Notezilla from the portable folder for a different user. Notezilla Portable keeps data in its own folder. So you can keep one portable folder for each user.
You can download the portable version from here: https://www.conceptworld.com/Notezilla/Download