Nutritionally is the adverb: judged by what the food does for the body, not by taste or price. “Nutritionally, brown rice and white rice are not the same.” A nutritionally balanced lunch is put together so the body gets what it needs — it does not mean the lunch tastes balanced. This is a school-and-label word. You will see it in reports and on boxes more than you will hear it in a night-market queue. It is nutritional with -ly on the end, the usual English way of turning that kind of adjective into “in that way / in those terms.” Though actually, students sometimes park it in front of a noun as if it were the adjective; the adjective is nutritional.