Q: created my photobook but can't get it shipped to Nigeria

That is not possible - Print products are only available in supported countries - http://www.apple.com/shop/help/print_products/routing

If you have a friend in a supported country and have a payment method in that country you can order it for shipment to them an have them ship

and some third party printers may be able to print and ship for you - PrestoPhoto is one possibility (I have no every used them and know nothing except their web site claims to be able to print books form all versions of iPhoto

be sure to preview your book and save the PDF to verify what you send (to Apple or others) - Preview a print project in Photos, iPhoto, or Aperture to avoid issues - Apple Support

LN