In a large skillet, saute onion and jalapeno in oil until tender. Remove with a slotted spoon and set aside.
Pour eggs into the same skillet. Cover and cook over low heat for 3-4 minutes.
Sprinkle on top the onion mixture, bacon, tomato, avocado and 1/2 cup cheese.
Season with salt and pepper.
Fold omelet in half over filling.
Cover and cook for 3-4 minutes or until eggs are set.
Sprinkle with remaining cheese.