Receive a notification in Spanish for your Nexus 7 (2013)? Read this immediately before updating13
According to Google's issue tracker, plenty of Nexus 7 (2013) users have received the Spanish language notification. Although reports indicate that some brave souls attempted the update, it seems that those that tried saw the file stop loading as the update petered out halfway through.
Since Google is now aware of the situation, we're confident that some resolution will come of this in the form of a new update. And if you do have the Spanish notification on the screen of your Nexus 7 (2013), fight the urge to tap on the 'Restart and Install' button. Nothing good can come from it, so you might as well wait for Google to push out the corrected notification in English, and announce that the update has a green light to install.
source: IssueTracker via AndroidCentral