How to fix Nexus 7 app update errors after installing Android 4.27
Luckily, there is an easy fix if you've come across this problem. It seems that it's a problem with the Google Account information, so all you have to do is go into Settings>Accounts, delete your Google account, then reboot your device, and re-enter your Google account info. Simple as that.
It should only take a couple minutes, and then you'll be right back to updating apps without any issue.
source: Droid Life