Overview only "nagios-plugins-procs" and "nagios-plugins-nrpe" installed, can check nagios alive.
of course, nrpe installed on remotehost.
on checked server, install nrpe, and set nrpe.cfg like bellow. command[check_nagios_procs]=/usr/lib64/nagios/plugins/check_procs -c 1: -a /usr/sbin/nagios
on checking server, install nagios-plugins-procs, agios-plugins-nrpe and place nagios_check.sh on directory you like, then set cron