Bring a large pot of salted water to a boil. Add the cheese tortellini and cook according to package instructions until al dente, about 3-5 minutes. Drain and drizzle with olive oil to prevent sticking. Set aside.
If chicken is not cooked, poach or bake until fully cooked, then shred finely. Slice roasted red peppers into strips or bite-sized pieces.
In a large mixing bowl, combine ricotta cheese, 3/4 cup shredded mozzarella, grated parmesan, garlic powder, dried basil, dried oregano, salt, and pepper. Stir until smooth and well combined.
Add the cooked tortellini, shredded chicken, and roasted red peppers to the cheese mixture. Gently fold together ensuring tortellini are evenly coated.
Preheat oven to 375°F (190°C). Lightly grease a baking dish with olive oil. Transfer tortellini mixture into the dish and smooth the top. Sprinkle remaining mozzarella cheese evenly over the casserole.
Bake uncovered for 20-25 minutes until cheese is melted, bubbly, and golden brown. Optional: broil for last 2-3 minutes for extra golden crust, watching closely.
Let cool for a few minutes before serving. Enjoy with a green salad or garlic bread.
