Sorry to hear that you are having an issue reconnecting your Google Home to your network.
A few questions — is your Nest Mini within 15 to 20 feet (5 to 6 meters) away from your router? Are there any other networking devices on your network aside from the wireless router, such as an extender, repeater, or another access point? Also, was it connected before to the same network?
Could you try resetting your Google Home. Also, before setting it up try reinstalling your Google Home app.
Looking forward for your response.