Katie,
It's an Advent story book - it has a story for each day of advent and some element of the story very easily becomes an addition to your nature table (not necessay, of course, but the story seems to lend itself well to that purpose).
For example, in the first story (working from memory from last year...) Mary is walking to Bethelem and the stones are rocky on the path, but she doesn't complain. An angel comes down and turns all the sharp rocks into smooth pebbles of many colors. So, I would lay out a path of colored smooth stones as that first element of my table (of course, I need to get making the people for the table too).
I like lanterns

We made one last year in a Rutabega that was neat, and I've done a couple made from watercolor paper and cutouts lined with tissue paper.
~amey