Preheat An Oven To 325 Degrees F (165 Degrees C). Melt 1 Tablespoon Butter In A Skillet Over Medium Heat. Cook The Chicken In The Butter Until No Longer Pink And The Juices Run Clear, 7 To 10 Minutes; Remove From Heat And Set Aside. Combine The Ricotta Cheese, 1 Tablespoon Butter, Garlic Powder, Oregano, Salt, And Pepper In A Microwave-Safe Bowl. Heat In Microwave For 1 Minute; Stir To Combine. Spread The Mixture Over The Pizza Crust. Scatter The Mozzarella Cheese Evenly Over The Pizza. Arrange The Cooked Chicken, Broccoli, And Mushrooms Evenly On Top Of The Pizza. Bake In The Preheated Oven Until The Cheese Is Melted, About 20 Minutes.