Whisk the egg whites, salt, and black pepper in a small bowl until the mixture is uniform and slightly frothy.
Place a 10-inch non-stick skillet over medium-low heat and add the olive oil, swirling to coat the surface.
Pour the egg white mixture into the skillet.
Using a heat-resistant spatula, gently lift the edges of the setting egg whites to allow the liquid portion to flow underneath.
Once the top is almost set but still slightly moist, fold the omelette in half.
Transfer the omelette to a plate and garnish with the chopped chives.