Why couldn't you use PowerShell to perform the grabs on the volumes, then simply set up a foreach on the object to go through and invoke the SSH command? Kind of a hybrid approach? Or I could misreading the ask here.
#*Psuedocode, do not use in production*
$creds = (get-credential)
$IP = "cluster_IP"
connect-nccluster -cred $creds -cluster $IP
$volumes - get-ncvolume
foreach ($volume in $volumes){
invoke-ncssh -cred $creds -IP $IP "volume modify -volume ($volume.name) -vserver ($volume.vserver) -tiering-minimal-cooling-days XYZ"
}