Fill a large pot with water and cook penne according to directions on box.
Meanwhile, chop the thawed chicken into bite-size strips. Set aside.
When the penne is done, drain and set aside; heat the pot with the olive oil and let the oil get really hot.
Add just under 1 TBSP of fresh minced garlic and add basil and onion. Stir around a bit and add the chicken. Sprinkle with salt and then sprinkle a lot of garlic salt. Add a little ground black pepper.
Stir fry until chicken is no longer pink, around 5 minutes; do not overcook, as the chicken will get tough!
Spoon the chicken into the bottom of a casserole dish that has been sprayed with non-stick cooking spray; glass looks really pretty. Spread penne evenly over that.
Pour marinara sauce over all and sprinkle mozzarella cheese over that. Sprinkle the cheddar cheese over everything, it should just be a thin layer.
Bake at 300°F until cheese melts, about 9-15 minutes.