A mole is a very large unfathomable number. For example a mole of bytes for computer information, on floppy disks stacked end on end, would be 825 trillion miles tall. This would take light 51.3 days to travel past.
Nano is a small prefix and it is hard to understand. The wavelength of visible light is in the hundreds of nanometers so one nano meter is even smaller than th light you can see yourself.