it's probably not going to stop. Might get a little better...
always add the lest aggressive fish first. Adding less agressive fish AFTER an agressive fish has already established it's territory yields this kind of result.
One thing you can do to try to stop it is rearrage the tank. Moving the rock work around resets the playing field. The
Naso Tang will have lost his safe spot, and it would put them both on even ground.
Keep in mind, the side affect to this will be additional stress to both fish...so make sure to keep a REALLY close eye on the tank. Try to ruduce any swings in Temp, pH, and salinity.
hope that helps, and keep us posted!