You can transfer files from one iPod to another using apps such as AnyTrans and Syncios iPod to iPod Transfer. You can also use iTunes if you're moving from an older iPod to a newer one.
Syncios iPod to iPod Transfer is compatible with Windows PCs and Macs. Download the appropriate setup at Syncios.com, and install the software in your computer. For the application to run smoothly, you should have iTunes installed in the computer. Connect the iPod with the files to your computer using a USB cable, and launch Syncios iPod to iPod Transfer.
Go to My Device, click the Media tab, and highlight Music. Select the files you want to copy, click Export, and choose a directory to save the files. Once the files are saved in the computer, unplug the iPod, plug in the other iPod, and open Syncios. Click the Media tab, highlight Music, and click the Import option. Navigate to the directory where you saved the files, select them, and import them to the iPod.
To transfer files to a newer iPod using iTunes, create a backup of the older iPod from iTunes, disconnect it, connect the new iPod, and restore the backup you just created to the newer iPod. The newer iPod should have all the files and the folder structure of the older iPod.