Sauté peppers and onions in butter until crisp-tender. Add mushrooms and taco seasoning; sauté until fragrant, about 2-3 minutes. Stir in chilies, olives, and 2 cups of salsa. Add meat, stirring until heated through. To serve, make a large X in the top of each baked potato with a knife; squeeze to open. Top with meat mixture; sprinkle with cheddar and Monterey jack cheeses. Garnish with desired condiments: sour cream, salsa, jalapeños, etc.