Yellow vs. Naso Tang

[naesco]

The aggression will likely subside as they get used to each other as your tank is large enough to accommodate them.
In the meantime feed the yellow tang at one end of the tank and the naso at the other so they dont fight over food.
As the naso is stressed make sure that you are feeding garlic extract and selcon soaked food to avoid an ich outbreak and, feed more frequently.
Good luck