In a medium bowl, whisk together the egg yolks, salt, pepper, and corn. In another bowl, beat the egg whites until soft peaks form. Gently fold the egg whites into the yolk mixture until no trace of white remains. Melt the butter in a large nonstick skillet over medium heat. Add the egg mixture and cook, without stirring, until the eggs begin to set but are still slightly runny in the center, about 1 minute. Draw the eggs from the edge of the skillet to the center and cook until almost set. Sprinkle half the omelet with 3/4 of the cheese and 3/4 of the chives. Using a spatula, fold the omelet over, forming a half-moon. Cook until set. Sprinkle the remaining cheese and chives over half the folded omelet. Fold the omelet again, forming a triangle. Slide the omelet onto a plate. Serve immediately.
Tip: If the omelet is still runny on top but beginning to brown on the bottom, place the skillet (if it's ovenproof) under the broiler for about 30 seconds before folding the omelet.