ipad nano will not power on

See the appropriate section of this Apple support document.

iPod nano (6th generation): Hardware troubleshooting

If you are still unable to get the iPod to power on, it's likely hardware related meaning you'll need to take or send your iPod in for service.

B-rock

Keep your iPod in charging for about 5 minutes first then try again.

If Not.

How old is your iPod?

Was it exposed to heat?

Was your battery previously faulty?

Is it still under waranty?

Was it exposed to water or drops or rain?