It was a long time ago that I worked with Oracle, and I know nothing about netmonitor.
But is not the information you want to check in flat textfile logs that you can easily reach from scripts outside Oracle and netmonitor?
If netmonitor works like Nagios, you can make it run your own script to make the check, and show the result of the test as you wish.
You could let the script select the log files with the correct date in the name and search them for the table name. If the log says it was created you set the exit code to 0 and output a line of text saluting the success. I there is error messages for the table creation in the log, you set the exit code to maybe 2 and output a suitable text. If your search get no hits, make it a warning with exit code 1, and an appropriate text.
It is my guess that Netmonitor would use exit code 0 for success, 1 for warning, 2 for failure and 3 for when a status has not been able to be determined.
I hope this could inspire you to a working solution