I opened a NetApp support ticket on this issue (Restore failed with error: The mount request was denied by the NFS server) and received the following information:
"Restoring DBs to instances hosted on different ESX hosts is not currently supported and will result in the above error. If the VMs hosting these instances are located on the same ESX host, there is a potential issue that we might be seeing."
In my case, the SQL VMs were indeed on different hosts. After migrating them to the same ESXi host I was able to perform the out-of-place database restore without issue.
I inquired as to when this operation might be supported and my tech explained there is a BURT open for the feature and they are looking at adding it in a future release but no version for the release has been selected since it is a complex undertaking.
Lynne