This might be a better question to ask in the NSP forum. I don't know about a report, there is a dashboard tab in the NSP Real Time Threat Analyzer ( "Hosts" tab) that allowed you to see what hosts are *currently* quarantined. You should also be able to see current quarantine actions in the sensor properties inside the ESM GUI.
You might also try running an NSP user activity audit report on the user ID used by ESM to connect to the NSM. That should show the quarantine action as well.