That's quite an exagerration. It has some stuff that's inspired by the Covenant books (most notably, the Giant race),
Actually, Giants comes second to the Oathsworn as far as being "based" on Thomas Covenant. And note that my comment was sort of in reply to "D&D is too based on Tolkien!". And I stand by saying that AU is just as based on Covenant as D&D is based on Tolkien.