Hi cotpusher1,
Thanks for the post in Apple Support Communities. I understand you're unable to install an app from the App Store.
Can you confirm your current iOS version, found under Settings > General > About? Also, which iOS version were you using prior to restoring your iPod, if you recall? It sounds like a possibility that your iOS software may be older than the minimum requirements to install the Audible app based on the error message you're receiving. Per this resource from Audible, you'll need to be able to run at least iOS 9 to install their app: What are the requirements to install the Audible App on an iOS device?
I hope this helps get you started.
Cheers.