I believe the Northern Lights are the result of the processes that God set up when he created the Universe. This is a question that each individual has to decide for themselves and that no can answer for you, because it depends on your definition of God's role in the physical processes of our world. Does God set up the physical rules that govern the behavior of our world and just sit back and watch (like a computer)?? Or does God play an active role in his creations, say, sculpting the very direction and choosing the color and intensity of the lights for our benefit?? It's for you to decide how you define it.
Personally, I think God is everything and everywhere. I believe he designed a physical world and set up processes to make it go and then created us and gave us the senses with which to experience it. Everything that exists is his handiwork, so anything that occurs as a result of the things that exist are his handiwork as well, not only by natural default, but because he
is his creation. For example, in the beginning there was nothing - void - and then there was an explosion of matter that produced our universe and the elements that make up everything that ever has or does exist. Most intelligent scientists would never try to convince you that they even have the tiniest fraction of an inkling as to what happened before or what caused this "Big Bang", all they can measure and dissect are the results of it. I personally believe it was the creation event. God created the universe from himself, because he is the only thing that existed, or exists. Before creation, during creation, and after, there is nothing but God. Wrapping my mind around that concept causes me a whole lot more awe and humility than a couple of pretty lights
! Although they are fantastic to watch!