My ipod Nano 7th generation could not hold for more than 2 seconds without the cord connected. What should I do?

Hello Chicharito_MU,
Thank you for using Apple Support Communities. I see your iPod has not been holding a charge. I know how concerning it can be when you're unable to use a device as expected. I am happy to help.
The following steps can help when your battery life seems short:

If the battery charge on your iPod seems shorter than expected, try these things:

• Make sure that your iPod has the latest software.
• Use the Lightning cable that came with your iPod to charge it and make sure it stays connected to your computer until it's fully charged.
• Make sure that your computer is on and awake while your iPod is charging.
• Adjust the display brightness. Go to Settings > General > Brightness and drag the slider to the left to lower the screen brightness.
• Turn off Equalizer (EQ) if you don't use it. Go to Settings > Music > EQ and select Off from the list. If you added EQ to certain songs in iTunes, you need to set EQ to Flat from iTunes because your iPod uses the same settings that you use in iTunes.

Learn how to maximize the battery life and lifepan

Get help with your iPod nano (7th generation)
Have an amazing day!

Hello Chicharito_MU,
Thank you for using Apple Support Communities. I see your iPod has not been holding a charge. I know how concerning it can be when you're unable to use a device as expected. I am happy to help.
The following steps can help when your battery life seems short:

If the battery charge on your iPod seems shorter than expected, try these things:

• Make sure that your iPod has the latest software.
• Use the Lightning cable that came with your iPod to charge it and make sure it stays connected to your computer until it's fully charged.
• Make sure that your computer is on and awake while your iPod is charging.
• Adjust the display brightness. Go to Settings > General > Brightness and drag the slider to the left to lower the screen brightness.
• Turn off Equalizer (EQ) if you don't use it. Go to Settings > Music > EQ and select Off from the list. If you added EQ to certain songs in iTunes, you need to set EQ to Flat from iTunes because your iPod uses the same settings that you use in iTunes.

Learn how to maximize the battery life and lifepan

Get help with your iPod nano (7th generation)
Have an amazing day!

Replace the battery.

Yes, you can take it to an Apple Store

Here is a support article that provides the info you need:

iPod Service Answer Center - Apple Support

Cheers,

GB