My iPod Nano, about two years old (model A1320), is giving me the message that it "may be corrupt." Anything I can do with it to avoid losing all its contents?
Not really. You might be able to use a third party extraction tool, but most of them require a fully functional iPod and software in order to work properly.
See this older post from another forum member Zevoneer outlining a few possibilities you may want to look into.