Hi there kjholland!
I have an article for you that can help you with troubleshooting your Nike+ syncing issue. The article will help guide you through the steps of troubleshooting, and can be found here:
If the issue is still unresolved after going through the steps in this article, there is a link at the end of the article that can take you to the troubleshooting assistant for your iPod nano. Thanks for using the Apple Support Communities!