Adapted from How to mount NFS share as a regular user - by Dan Nanni:
In order to allow a regular user to mount NFS share, you can do the following.
On the NFS client host (e.g., 10.1.1.20), update /etc/fstab as root.
$ sudo vi /etc/fstab
192.168.30.26:/root/backup /usr/backup nfs rw,noauto,user 0 0
In the above, "user" allows a non-root user to mount, and "noauto" means no automatic mount on boot.
On the NFS server host (e.g., 10.1.1.10), enable export for the client as root.
If you want to enable export non-permanently (which is not persistent across reboots):
$ sudo exportfs 192.168.30.26:/export -o rw,async,no_root_squash,no_subtree_check
If you want to enable export permanently (which is persistent across reboots):
$ sudo vi /etc/exports
$ sudo exportfs -a
Now you can log in as "user" on the NFS client host, and do NFS mount as follows.
$ mount /usr/backup