The key to crunchy granola is to bake it at a low temperature for an extended period of time. This way the nuts and seeds don't burn but the granola can slowly dry out. I also recommend stirring the granola to ensure it will brown evenly. If your granola should be chewy after baking, return it to the oven for an additional 5 minutes or so to dry it out more thoroughly. You can also just allow it to sit in the turned-off but still warm oven.