You can see Wi-Fi specifications for the different Nest Wifi units here:
Then search up specifications for your specific iPad model to see if it supports the specs of your Nest Wifi.
You could try to make sure that WPA3 is disabled, it might help with compatibility for older devices.
Thanks for the info, olavrb.
I just wanted to jump in real fast to see if you saw olavrb'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.