I'm not sure I'm reading your question right, but here goes.
It sounds like you're using vSphere Replication today to replicate at the VM-level using host-based replication. That's awesome.
If you want to protect at the datastore level, NFS included, then you're looking at using array-based replication. In this case, VMware has you covered as well with the full-blown vCenter Site Recovery Manager (SRM) product. With SRM, your storage vendor software is responsible for the actual replication and SRM provides the back-end scripting and automation, using a hook or plug-in to your storage array (written by your storage vendor), to orchestrate and manage site-to-site failover.
Cheers,
Mike
https://VirtuallyMikeBrown.com