pmp-check-mysql-status -l $USER3$ -p $USER4$ ......

The command like this “pmp-check-mysql-status -l $USER3$ -p $USER4$ -H $HOSTADDRESS$ -x Threads_connected -o / -y max_connections -T pct -w 80 -c 95” should go to the nagios config and nagios replaces those vars with the respective values.