If it's already nipping corals the chances of it stopping are slim, but you will probably at least see a reduction.
While I realize that this is not going to hold true for everyone, I have kept quite a few dwarf angels and two large marine angels (albeit juvies though) and have noticed that they will all pick on corals when not given another option. In fact, like I mentioned before, the same can hold true for some butterfly fish (my banner fish exhibit the same behavior) and alot of the tangs too (although they may be less prone to nip on corals themselves IME, but mine have disturbed corals while picking at algae on a rock).
That being said, I honestly do not think most of us will find any great success in reducing coral nipping in many angels by simply feeding them a larger amount of food...even if we are feeding them in the morning, at noon, and at night - although this might reduce the problem to some extent but then overfeeding becomes an issue...but the most effective 'trick' I have found are those algae/seaweed sheets
coupled with a once daily feeding of other foods (e.g. flake foods, spirolina...and to be honest, 99% of the time I feed frozen foods because this allows me to use vitamin C and garlic supplements with ease).
Again, I realize that this may not hold true for everyone...and I am sure someone will disagree with me...and of course, I haven't kept every angel in the world either. However, my point here is that providing a source of food which angels can graze upon at any given time has been more effective for me versus feeding more often during the day, or in larger amounts.
Additionally, I have also found great success in tying a veggie clip to an algae magnet with a short piece of fishing line and using that to hold the algae/seaweed. This has helped in two ways - 1. It allows me to position the food in the most ideal spot, whether that be in the area my angel 'hangs out' in the most or out of the way of a stronger water flow because I have noticed this leads to the algae/seaweed falling apart more quickly and 2. I have found that this is an easier method to use when trying to remove the uneaten portion of the algae/seaweed since, when I used to try grabbing it with my hand, it would fall apart so now I simply move the algae magnet to the top of the tank and net the stuff out. In fact, I actually began using this method when I started keeping a fox face, and until recently, my fuzzy dwarf lionfish, because it allowed me to keep my hands and arms out of the tank.
Sorry to babble on here...just wanted to expand upon my previous advice a bit....and also because, while I agree with Lynden in that this might be a tough habit to curb in your instance jeasko, I have a hunch this 'grazing foodstuff' might be your best bet.