choffman PRO said over 2 years ago on Sign in with Apple :
Hey Alana - Unfortunately, no I did not find a good solution. I had to move on to other tasks. I was able to find the line of code in the Gem that caused the nonce error, removing or suppressing it didn't seem like a good idea. Let me know if find anything that might work. 

FYI - 
The issue has been reported to GitHub: https://github.com/nhosoya/omniauth-apple/issues/76