Thanks for posting.
To answer your question, Google Nest Hub and other Google Nest speakers can't be connected to Amazon devices.
If you want to connect other devices on your Google Home/Nest speakers, you can check it from the Google Home app partners by accessing or trying to add a device. Simply tap on the "+" sign on the upper right corner of the Home app, select "Works with Google" and from there, your can see all available partners that you can connect with your speakers.
Hope this answers your question.
I want to ensure you are good to go, and everything is working properly. Please let me know if you are still having trouble, as I will be locking the thread in 24 hours due to inactivity.