I purchased a new construction house in April that had 2 Nest Es installed so they cannot be very old. They both worked fine for several months but about a month ago one completely stopped being able to recognize ANY wifi network. The other is still working fine.
It looks like I'm having the same issues shown here: https://support.google.com/googlenest/thread/19997505/w5-error-problem-have-tried-all-the-troublesho...
If you have done all the troubleshooting steps, and especially if the Nest E cannot see wifi networks, then yes I would suspect that the Wifi chip has gone dead, you will need to contact support to see about getting a replacement unit.
You can request a call or chat with the google store here:https://support.google.com/store/gethelp
I just wanted to jump in real fast to see if you saw Ashepherdson's reply and to see if you still needed some help on this or if you were able to get it sorted out. If you are still needing some help, just let us know and we'll be happy to continue helping.