Thanks for reaching out.
What specific Google Nest device do you have? If it is one of our Nest thermostats, you need to Use a screwdriver to loosen the screws of the base then gently pull it off the wall.
We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.