Nursing bra question?

I'm a FTM so please don't judge my lack of know late of these things.. Lol. Is a nursing bra just for if youre nursing or is it called a nursing bra because it's for women who have just had a baby? I'm in need of some comfy bras for after birth; but I am not nursing, should I still get a nursing bra for comfort? Or is it only for if you're nursing?