Using my Arduino nano with IDE 1.8.8 I had trouble uploading a basic program on board.
It was impossible by setting tools/board/arduino nano but worked when setting tools/board/arduino Pro or Pro mini
Thanks for sharing your solution. The more common (and official) solution to this issue is to select Tools > Board > Arduino Nano and then Tools > Processor > ATmega328P (Old Bootloader). Either will work, but it might seem more logical to still be able to use the Nano board selection.