Nerve-wracking is an adjective used to describe things or situations that are stressful or cause anxiety. The speaker has used to express his feelings being in the competition, as there is a lot of pressure placed on contestants right from the start. You can use nerve-wracking to describe similar situations.
Ex: My exam starts in an hour. It is incredibly nerve-wracking.
Ex: Giving a speech in front of other people is a very nerve-wracking experience.