Preheat oven to 375 degrees F. Loosely wrap stack of tortillas in foil and put them in the oven for 15 minutes to soften. Saute onion in butter until slightly soft. Add green chiles. Add lightly beaten eggs, salt , and pepper to taste. Cook over low heat until soft but not set. Fold in 1-½ cups cheese. Divide egg mixture evenly among tortillas, spreading down center of each. Fold in sides of tortilla and secure with toothpick. Fill large baking pan (sprayed with non-stick cooking spray), placing tortillas side by side. Sprinkle remaining cheese over top. Bake for 20 minutes or until the cheese melts and the tortillas are heated through. Serve with sour cream, salsa, and chopped tomatoes.