Preheat oven to 425. Grease a 9 inch skillet or pie dish and set aside.
Combine sour cream, mozzarella, provolone, Parmesan cheese, and Italian seasoning in medium bowl and mix together. Pour cheese mixture into pan and make sure to leave a little room at the top of the dish, since it bubbles up while cooking.
Bake for 15 minutes until dip is melted and lightly browned on top. Garnish with green onions and serve immediately with sliced bread.