Your question lead me to guess that you are very new at marine aquarium keeping.
Yellow tangs will eat essentially everything. If your tang does not eat it is because of his health or he is too new in the tank. Given a little time, if he is well and when he is comfortable, he will eat. Which brand of food, or which brand of Nori does not make any different. Since the food that you feed him in captivity does not look like food he eat in the wild, it maybe a little bit before he learn that these are food.
Start out with frozen then mixed flakes or what ever you feed your tank with it. He will learn quick enough. He learn quicker if other fish that are eating well in the tank. Once he see them eat it, he will try and start.
Feeding Nori is a little more difficult. You need to attach it some where in the tank. If there is another fish already eating it, it will be easy. Otherwise, when the nori come apart and float around, he will sample it and eventually learn to eat it on the clip before it come apart.