Install the latest version of iTunes on your computer
Connect the iPod Nano to your computer using a USB cable
Open iTunes
Select the iPod Nano when it appears in iTunes
Add music to your iTunes library if it is not already there
Choose the music you want to sync
Click the device summary or music sync section
Enable music syncing
Select the playlists, artists, albums, or genres you want to transfer
Click Apply or Sync
Wait for the transfer to finish
Eject the iPod Nano safely from iTunes
Disconnect the iPod Nano from the computer