You’re using Kodis’s NFS stack whereas there is also a kernel method with better performance for which you have to configure /etc/fstab, see Configuring fstab based NFS share mounts.
In summary:
- remove your current NFS based source from kodi
- configure NFS access using /etc/fstab
- re-insert the source in Kodi but think about it is now a location in the root file system