Hello ahall561,
Welcome to Apple Support Communities!
We can help ensure the devices are working as expected and look into your sync options.
We want to make sure you're using these steps to sync:
"Sync all items of a content type
- Connect your device to your Mac.
You can connect your device using a USB or USB-C cable or using a Wi-Fi connection. See Sync content between your Mac and iPhone, iPad, or iPod touch over Wi-Fi.
2. In the Finder on your Mac, select the device in the Finder sidebar.
If you connect your device to your Mac using a USB cable and don’t see the device in the Finder sidebar, see If your device doesn’t appear in the sidebar.
3. Click the type of content you want to sync in the button bar.
Note: If you use iCloud Photos and Apple Music, your photos and music are synced automatically using iCloud. When you click Music or Photos, no options appear for syncing.
4. Select the “Sync [content type] onto [device name]” checkbox to turn on syncing for that type of item. For example, select the “Sync movies onto [device name]” checkbox to sync your movies.
With the checkbox selected, syncing is set to transfer all items of that type to your device.
5. Repeat steps 3 and 4 for each type of content you want to sync.
The bar at the bottom of the window shows how much free space remains on your device after you sync. Move the pointer over the bar to view details about the content you’re syncing.
6. When you’re ready to sync, click Apply."
This Apple Support page has the full details: Sync content between your Mac and iPhone, iPad, or iPod touch - Apple Support
If the issue continues, which iOS version is the iPod using? Does restarting both devices and testing again have any impact?
We hope this helps to resolve the issue so you're able to sync.
Cheers!