Check out state dept quote.
The concept of dual nationality means that a person is a citizen of two countries at the same time.
In my opinion that means that someone with dual nationality can't be "Natural Born".
My father had dual citizenship at birth; US and Canadian. He made a point of telling me that he couldn't be POTUS. I may not even be eligible by some of the stricter interpretations I've seen here. I also wouldn't want to be. I am not qualified although if thrust into the role I would do my best.