To add a NFS datastore to a single VMHost:
Get-VMHost "HOSTNAME" | New-Datastore -Nfs -Name "DATASTORE_NAME" -Path "VOLUME_MOUNT_PATH" -NfsHost "IP_OR_HOSTNAME_OF_NFS_HOST"
To add a NFS datastore to all VMHosts in a Cluster:
Get-Cluster "CLUSTERNAME" | Get-VMHost "HOSTNAME" | New-Datastore -Nfs -Name "DATASTORE_NAME" -Path "VOLUME_MOUNT_PATH" -NfsHost "IP_OR_HOSTNAME_OF_NFS_HOST"
