What model iPod nano do you have? Does it have a touch screen (6th or 7th gen), or is it an earlier model with a click wheel?
If everything on the iPod is in your iTunes library on the computer, you could just Restore it in iTunes. That will erase the iPod, re-install its software, and set it to default settings (where you can select language).
There is a less drastic command to Reset Settings on the iPod. It is the last item on the iPod's Settings screen. So even if you can't read the text in Chinese, if you can find the Settings screen, try the last item. Reset Settings asks you select language.