The guys from Droid-Life got news that the Android 4.2 update on the Nexus 7 causes some issues with the Play Store, basically breaking it. Constantly returning that there was an error downloading apps. That is definitely an issue Google will need to get resolved ASAP. There is a solution to help you get back to your daily life though.
Wiping data and force stopping the Play Store does nothing, the solution is to remove the Google account, reboot, then re-add the Google account. It’s quite the process but the issue is solved instantly. It is better than sitting around wishing you could download an app or an update.
Source: Droid Life