This is not the experience we wanted you to have, let me help you. A few things: was the Duo calling working before with your Nest Mini? Were there any recent changes made? What country are you in and what phone do you use when setting up Google Home?
Go to your phone’s settings and ensure the language is set to EN-US or just EN and try again. You might also want to enable Personal Results from the Google Home app, here’s how:
See this guide for more information about Duo calling.
Keep us posted.