The loose axle nut noise is more like a thunk when you start and thunk when you let off the accelerator or tap the brakes, basically when you cause the axle to push or pull differently than before.
When driving around in any parking deck with the windows open, I hear all sorts of noises from the car, some like this. I also hear squeeks and squeals from the calipers slightly rubbing against the rotors. I've concluded that because the car it so quiet. You can pick out these noises. Most ice vehicles have an engine running which tends to drown out these noises.