I believe it is Nuh-vay-uh as well.
I don't personally care for the name just because it's so trendy at the moment. I feel like everywhere I turn, there is another baby girl being born and named Nevaeh. I am assuming mothers are choosing the name because of the "Heaven backwards" thing but then why has nobody just named their child plain old Heaven?
Oh well, it doesn't matter to me whatever anyone wants to name their baby.