Nuremberg only applies if the person "following orders" KNOWS that he is doing something wrong. In this case it wouldn't apply unless the Admiral had direct knowledge that trump was drunk as opposed to it being a response to a Chinese/NK launch. 

The Nuremberg trials only prosecuted 200 people. Those responsible for giving the orders and some high level actors responsible for carrying them out who had a reasonable amount of information and knew or should have known that they were "war crimes".  Military trials prosecuted another 1600 for crime against humanity committed during the war.

There were THOUSANDS of officers in the German military that carried out orders for the Third Reich that weren't prosecuted because they were following orders and had no reasonable way of knowing that their actions were technically illegal according to international law. (ie: I was ordered to bomb the town so I did. I had no way of knowing that the order was given because the town was Jewish.)