Preheat your oven to 400°F.
In a medium bowl, combine the cubed chicken, minced garlic, oregano, Italian seasoning, salt, and black pepper. Toss well to coat the chicken evenly.
In a deep skillet that is oven-safe, melt the butter over medium heat. Add the seasoned chicken cubes and cook for 7-8 minutes until they are fully cooked.
Turn off the heat and add the sun-dried tomatoes, baby spinach, uncooked penne pasta, and Alfredo sauce to the skillet. Mix well to combine.
Pour the boiling water over the mixture and stir until everything is evenly distributed.
Cover the skillet with a lid or aluminum foil and transfer it to the preheated oven. Bake for 30 minutes or until the pasta is cooked through.
Remove the skillet from the oven and sprinkle the mozzarella cheese over the top of the pasta.
Return the skillet to the oven and bake for an additional 5-10 minutes, or until the cheese is melted and bubbly.
Garnish with fresh basil or parsley, if desired, before serving