Warning! Nano Clones with Mega328PB-U Chips.

Well at least you have two extra digital IO pins on A6 and A7 as a consolation prize. The ATmega328PB is a bit cheaper than the ATmega328P so I suppose it's not surprising but I'm sure this could cause a lot of confusion for someone with less experience.

I found a problem with the beta version of Arduino AVR Boards required by MiniCore for the PB chips:

That's only an issue if you use the "Arduino as ISP" programmer. I also ran into a problem with the compiler that forced me to stop using it. It only occurred when compiling a very large and ugly code with a lot of templates and it wasn't consistent so I never got around to reporting it to Arduino. I forget the exact error but it wasn't a code error, but rather a glitch in the compiler itself.