Is the navigation controller's root view controller the same as that of the window's when set?

Just a question I have that doesn't appear to have been directly answered here before.

I have a simple app using storyboard which has a navigation controller set as the initial view controller in the storyboard, and the first view controller set as the navigation controller's root view controller.

I've read that the window has exactly one root view controller. Is that, then, in this case the navigation controller itself, since it's the initial view controller, or does the window share the navigation controller's root view controller?

Thanks in advance for any help.