That was the one with the kids playing as Orcs. I've read it. I don't remember anything relating to a Nazgul - it really was very short. Bear in mind that Tolkien spends so much time describing stuff it takes him forever to move the plot along...
I may be mixing up the volume and the story. I just remember the commentary on a story saying that Tolkien was considering a story with the Lord of the Nazgul as the villian. In LotR it doesn't say much about what happened to the Nazgul and the power of their rings. The three Elven rings lost power but I don't remember anything about the human and dwarf rings.
This goes back to childhood when I so very much wanted more Chronicles of Narnia or stories about Hobbits, Ents, Elves and Dwarves. A few years later the Sword of Shannara was published and since then dozens of Tolkien knock offs. None of them as satisfying as the original.
Hm . . . I'm surprised they didn't do Shannara instead of Eragon.
If they do all 7 of Narnia and they perform as well as LWW will they move on to Lewis's space trilogy? And what would the rating be for Perelandria?
. . . I'd better stop. This is becoming a stream of consciousness post.