We use to feed lots of the Romaine lettuce and such, way back in the 70,s and 80,s.
I think its mostly a filler but not very nutritious. However its better than not feeding any leafy greens to tangs.
Mine dont seem to like green nori much. Perhaps its the wrong kind. They do like Julian Sprung,s Sea veggies. Most colours. Their staple and favorite is still spirolina flakes. Like others they also eat most of the frozen foods I feed the others.