No - A LUN is created within a volume on ONTAP. If nosnap is set to on, how would snapdrive create the snapshot of a LUN in a volume that wouldnt let it?
Snapdrive issues the commands to ONTAP to create the snapshots of the LUN's, at a given time, date etc. It just presents these options, along with others, in the form of a nice GUI.
It also have the ability to run other application commands that ONTAP doesnt, such as the ability to quiesce a database, before taking a snapshot, so the data is in a consistent state.