If you used automatic syncing, an iPod syncs with an iTunes library, not to an account, such as your iTunes Store account (Apple ID). So, if you still have the same iTunes library, it should still work with that library, even if you no longer have access to an "account."
However, it can only sync with one iTunes library at a time. If it is currently set up to sync to an iTunes library that you no longer, you can set it up to sync to your current iTunes library. But when you do that, the iPod's existing content is replaced by content from that iTunes library.
If that iPod was previously set up using the Manually manage music setting (you dragged songs to it in iTunes to load it), instead of automatic syncing, it is NOT syncing to a particular iTunes library. In that case, you can add new items to it from your current iTunes library. But you cannot set up automatic syncing without replacing its existing content.
You can post back to clarify your situation, and what you ideally want to do.