Preheat oven to 350.
Cook penne pasta according to the instructions on the box.
Heat olive oil and butter in a large skillet; add chicken, mushrooms, garlic and carrots; cook until heated through, and carrots are fork tender.
In the meantime, in a small mixing bowl whisk together broth, salt, pepper, garlic powder, italian seasoning and flour; whisk until completely combined.
Add to skillet with chicken and stir.
Stir in milk.
Cook and stir until thickened and bubbly.
Add cream cheese and continue to cook until cream cheese is smooth, stirring frequently.
Remove from heat.
Add pasta mixture, chicken mixture and tomatoes; toss to coat.
Transfer to a 3-quart casserole dish.
Cover with foil and bake for 30 to 35 minutes, or until heated through.
Remove foil, stir mixture and sprinkle with cheeses.
Continue to cook for 8 to 10 minutes, or until cheese is melted.
Remove from oven and let stand 5 minutes.