My Nissan quest will not turn over. We know that is not the battery because there is power. It sounds like a blender and we're not sure what it is.

Sounds like your starter motor is only half engaging the fly wheel. If it's grinding like a blender, that's most likely the issue. Rap on the starter a few times with a hammer, then hit the key again. If it still is grinding, I would just replace the starter. But before replacing the starter, I would also put a volt meter on your battery with the engine off. If the volt meter is showing less than 11.8, I would suspect that your battery may not have enough life to fully engage the starter motor. It may have enough power for the lights but nothing like a starter motor. If the battery is over 5 years old, it may be on it's way out.