In one sentence: I think anyone who has any interest in graphic novels will enjoy Nausicaä, either for the art or the story, and I definitely recommend it.
This review will contain spoilers!
In many sentences:
The art in this book is absolutely phenomenal. I don't read a lot of graphic novels, but I find that I really enjoy them the most when they really utilize the combination of art and dialogue to make something unique. While a talented writer could certainly bring the life a fantastical world, like the one we see in Nausicaä, I don't think I ever could have imagined it quite the way it appears in Miyazaki's art. It's so creative, so different, and so obviously inspirational that it is enjoyable to simply look at the art on each page.
Fortunately, the story and dialogue that the art supports is also entertaining. While the message may be a little heavy handed at times, it is also a message I can support. I did find it confusing here and there, attempting to follow along with the various plot points, the different characters, and the intricate geography, but not so much so that it interfered with my enjoyment.
I think anyone who has any interest in graphic novels will enjoy Nausicaä, either for the art or the story, and I definitely recommend it.