Preheat oven to 375 degrees. Bake potatoes until tender. Remove from oven and let cool. Cut each potato in half. With a spoon, scoop out some of the potato pulp. Season with salt and pepper. Bake potato halves until crispy. Mash potato pulp, stir in sour cream, parmesan cheese, mozzarella cheese, sun-dried tomatoes, green onions, parsley, spinach, and chard. Mixture should be sticky. Divide the mixture between potato skins. Sprinkle with black pepper and bake 15 minutes. Remove from oven and serve warm.