Standard use of this command is to add or list your NFS mounts.
List: esxcfg-nas –l
Add: esxcfg-nas –a –o <host> -s <share> <name>
Not much more I can say. A little more detail here:
A thread in the communities about a problem someone had where the nfsclient wasn’t loaded:
So go out and add some NFS datastores!