This is pretty much what you have to do when an opponent does an anticipatory roll forwards or backwards.
In fact, I pretty much always backdash after every combo unless the opponent is showing obvious hesitation... in which case I will usually 2C -> Throw -> whatever in air combo I canget going. Nu doesn't have alot of rushdown ability, but she has TONS of wallbounce, which I recommend using to the fullest against an opponent that is trying to be dodgy. It also helps to utilize 2D, 5D, and 6D.
Hope that helps.