The NCP command SHOW KNOWN NODE COUNTERS has no equivalent in NCL.
    However, you may obtain similar information using the "show know
    node counters" task of the Network Management GUI.

    You may wish to enable the displaying of NCL commands in that
    utility in order to see what NCL commands are necessary to produce
    the output.

    For more information, refer to HELP NETWORK_MANAGEMENT TOOLS GUI.