Nano originally synced to PC-what will I lose?

I am sure this subject has been addressed previously; my apologies, but I couldn't find it with several searches.
My iPod Nano (7th gen) was originally synced to a PC. I now have an iMac, and want to sync it there. I have a book and several tunes which were not acquired through iTunes. Will I lose them? If so, is there a work-around?

If you attempt to sync a Nano (or any other iPod) to a Mac that was previously synced to a PC, iTunes (on the Mac) will tell you that your Nano will have to be reset for the Mac. That means you will lose everything on the Nano. You will need to make sure that you backup what is already on the Nano before attaching it to your Mac and opening it in iTunes and allowing iTunes to do a reset.

Thanks! I have some audio books and some special-use tunes in my library, which on my iMac only show up in iTunes under Home Sharing. Can I get them back on to the Nano somehow? They are there presently, and I don't want to "lose" them.

Yes, you can get them back on your Nano. Copy whatever books and music you have on your PC to the Mac and into the iTunes library. Then whenever you reset and sync the Nano from the Mac, the books and music will get copied to it. Just make sure that you have everything backed up somewhere else in case things don't flow properly.