Every once in awhile it is common for an app to not open successfully on iPod even though you are tapping on the icon. If this happens to you sign out of your account by tapping on Settings and the iTunes and App Store. After you are signed out, force close the iTunes store app by double tapping on the Home button and swipe left or right until you find the app. When you find the app you can swipe to close it.
When the app has closed, restart your iPod and sign back into your iTunes account. The app should respond normally and open without an issue. If it does not you might have to uninstall and reinstall the app, contact the app developers to see if there are any issues that need to be corrected with the app, or restore your iPod. Make sure you have a current backup of your data before restoring it though so you don’t lose important music, videos or images.