Place the bacon in a cold, large cast iron skillet or other oven-safe skillet. Turn heat to medium and cook on the stovetop until the bacon is crispy, turning often. Remove the bacon and drain on paper towels. Add the potatoes and onions to the hot bacon grease, add a large pinch of both salt and pepper, and stir several times to mix well. Raise the heat to medium-high and cook until the potatoes start to brown on the bottom, about 6 minutes.
Whisk the eggs in a mixing bowl, add 1 cup of the cheese and a large pinch of salt and pepper, and stir to combine. Pour the egg mixture over the potatoes, sprinkle the remaining cheese on top, crumble the bacon on top, add the green onions and chilies, and bake for 10 minutes or until the eggs are set. Serve with salsa and sour cream, if desired.