Does a 2nd generation ipod nano have audiobook?

"i believe not. even if it did, you might as well buy the book: audiobooks are not cheap"

Yes, the iPod Nano Gen2 can play audiobooks from any source, such as Audible. If you find those to be too expensive, look for free audiobooks on Librivox.org. Hundreds of classics, in the public domain, are read by volunteers.