The event only says A new node (nodeLabel) was discovered by OpenNMS. in the log message and event description.
I would suggest to have different content in logmsg and description and also discovered is the wrong word because not only nodes that were discovered by the discovery trigger this event.
logmsg: A new node (nodeLabel) was added.
descr: The node (nodeLabel) was added and is now being monitored.
operinstruct: This event is purely informative. Please make sure that the newly added device $LINK_TO_NODE_PAGE is monitored as desired.