I had very little memory of the movie from my first viewing. I remembered giant insects, a forest, danger, things on fire. I remembered the gorgeous animation, easy to see even in the bad copy I was watching.
Seeing it again, after having seen almost all of Miyazaki's work over and over again, I was struck by a couple of things. First, Princess Nausicaä herself is a goody-goody, almost too perfect. Geeklet [age 8] was very impressed with her and found her something to aspire to. I wondered what would happen if she made a big mistake; The Maw [age almost-5] agreed that bad things have to happen or it's bo-ring. However, I do love that Nausicaä, despite her almost-mystical skill with insects and animals, is a scientist. She has her own lab and makes important discoveries for the future of the world. And she does suffer loss, quite a bit of loss, and she's pretty brave about it.
The other thing that really struck me is how closely Nausicaä of the Valley of the Wind  falls to Princess Mononoke . In fact, the stories are almost the same, except Nausicaä is definitely science fictional, whereas Princess Mononoke uses the mystical/nature spirit approach. Nature is Red in Tooth and Claw in both stories, both have a powerful female figure who wants to destroy the jungle/forest with Science/Industry, both have a young girl who is close to nature, both have villages threatened by monsters, both have war. In Nausicaä, the poisoned jungle is a result of human acts, centuries past. In Mononoke, Industry is just beginning to destroy the forest and upset the ecological balance.
ETA: both have a young man who's suffered damage at the hands of the main conflict, who becomes involved with the young woman. In Nausicaä, he's lost his twin sister to war. In Mononoke, his village is attacked as a result of industrial depredations.
Princess Mononoke, the character, is very different from Princess Nausicaä. She's feral, and can talk to wolves. But in her own way she has the same mystical link with the forest as Nausicaä does with the toxic jungle.
Nausicaä, so far as I know, was Miyazaki's first big film. It's fascinating to see how he carries the same themes throughout his career.