Nutritious describes food that's good for you. Brown rice and kale are nutritious, but jelly beans, sadly, are not.
Something that provides nutrients — vitamins, minerals, and protein, for example — is nutritious. Our bodies need nutritious food to grow, heal, and stay healthy, however much we might crave tasty, non-nutritious snacks. The adjective nutritious comes from the Latin word nutritius, "that nourishes," which in turn comes from the root nutrix, "nurse."