Can I completely wipe a Galaxy Nexus A friend of mine is considering selling his Galaxy Nexus (to me) and we wanted to be sure that if we did a hard reset it would wipe all data linking him to the phone.  I understand it utilizes a lot of core Google technologies and we don't want to find out down the road that something survives the process.

This is one of the unlocked Galaxy Nexus (GSM) purchased from Google
Yes you can. 

Actually, wiping an (unrooted) Android device is relatively easy. Just go into Settings and look for Backup &amp; reset option. At the very bottom of the options you'll see Factory data reset, hit it and you'll see some confirmation dialog, go through that and your "new" Galaxy Nexus will be ready in a couple of minutes ;)

This method will compeletly erase anything stored on the phone's internal storage, including all Google-related data.

Note that it's a good practice to also erase the sdcard partition alongside the process. Some Android application uses the sdcard partition to store user data which might be restored even after you wiped the device.

Good luck! :)