Hi!
I dig a little deeper and you cannot restrict what showmount will show based on an export policy. And this is not something with ONTAP. It's with NFS servers in general.
You can see though that the output, at least, does not show who has permissions (it states "everyone", even though that is not the case). So once permissions are fine, you'll be fine.
If your applications do not require showmout to work, I suggest disabling it:
cluster ::> nfs server modify -vserver NFS83 -showmount <enabled/disabled>
Otherwise you may try with the security/network team to implement something on their side, but I don't know what can be done specifically.
This community post has other suggestions: https://community.netapp.com/t5/Network-and-Storage-Protocols/Hide-NFS-exports/td-p/13777
Regards,
Pedro