how do i import music from my iPod nano to my mac desk top then export the music to my iPod touch?

Hey there Antonio7,

You can transfer your iTunes purchases from your iPod nano to your computer with this article:

Re-download or transfer your iTunes Store purchases from an iPhone, iPad or iPod to a computer

Transfer your purchases to your computer

Before you transfer your purchases, make sure that your computer is authorized with the same Apple IDaccount you used to make the purchases. Learn how to authorize your computer using iTunes.

If you bought the iTunes Store content on your device using multiple Apple ID accounts, you'll need to authorize the computer for each one.

To transfer purchases from your device to a computer:

1. Connect your device to the computer. Wait for its icon to appear in iTunes.
   
2. Go to File > Devices. If you're using iTunes for Windows and can't see the menu bar, learn how to turn on iTunes menus in Windows.
3. Choose Transfer Purchases from [device name].

​​This feature works only for content bought from the iTunes Store. Any items that you imported from audio CDs or received from other sources won't copy from your device to the iTunes library. However, all podcasts from your device's Podcasts app and copies of all PDFs and books from your device's iBooks app will transfer to the computer. Learn how to transfer media to your iTunes library.

Then you can sync the music to your iPod touch in the same way you sync music to any device:

Sync your iPhone, iPad and iPod with iTunes using USB - Apple Support