Looking around I found this old discussion which shows they are internally very different: the original Nano is basically a slimmed Uno, using the most common CPU in the Arduino ecosystem; the new Nano Every has a more powerful, but different, processor. Note that both are in a completely different league compared to the ESP32 - vastly less performance and no networking (WiFi/BLE) features.
I would say, check the libraries you would like to use in your project, to see if they are compatible with those boards (or CPUs).
In the case of the Nano ESP32, I'd go for "always win": you can't use that pin for anything sensible in your sketch (there is no pin called B1!), and the only function you will lose is the ability to enter ROM recovery mode via external logic - a questionable "feature" IMHO 
Happy hacking!