Shred the cooked rotisserie chicken into bite-sized pieces.
Wash and halve the cherry tomatoes, then chop the spinach.
In a large skillet, heat olive oil over medium heat, add cherry tomatoes and sauté for 3-4 minutes. Stir in spinach and cook for an additional 2 minutes.
In a large mixing bowl, combine shredded chicken, sautéed vegetables, heavy cream, mozzarella cheese, and Parmesan cheese. Add Italian seasoning, garlic powder, onion powder, salt, and pepper. Mix well.
Spread uncooked penne pasta in a 9x13 inch baking dish, pour the chicken mixture over the pasta, and spread evenly.
Cover with aluminum foil and bake in a preheated oven at 375°F for 25 minutes. Remove foil and bake for an additional 15-20 minutes until cheese is bubbly and golden brown.
Let the casserole cool for 5 minutes before serving.