No, Google Nexus customer service reps cannot see when you've performed a FDR (Factory Data Reset). The Factory Data Reset is a process in which all the settings, applications, and data stored in a device’s memory are brought back to original factory settings.
When you perform a Factory Data Reset, the device itself does not provide any information to customer service representatives. This means that Google's customer service reps cannot access any of your history and personal information stored on the device.
Google's customer service reps may be able to view some system-generated logs when troubleshooting but only with your permission. This log information is completely separate from any of your personal information stored on the device such as contacts, photos, and other data.
To read more about how to perform a Factory Data Reset for your Google Nexus device please visit the following page: [INSERT LINK]
If you have any further questions regarding Google Nexus customer service please reach out to the team directly. You can contact them using the following link: [INSERT LINK]
I hope this helps!