First, preheat your oven to 400°F.
Next, in a medium-sized bowl, combine the cubed chicken, minced garlic, oregano, Italian seasoning, salt, and black pepper. Give it a good toss to coat the chicken evenly.
Now, in a deep oven-safe skillet, melt the butter over medium heat. Once melted, add the seasoned chicken and cook it for 7-8 minutes until it’s cooked through.
Turn off the heat and add the sun-dried tomatoes, baby spinach, uncooked penne pasta, and Alfredo sauce to the skillet. Mix everything well until it’s all combined.
Pour the boiling water over the mixture and stir to combine everything nicely.
Cover the skillet with a lid or aluminum foil and carefully transfer it to your preheated oven.
Bake for 30 minutes or until the pasta is cooked to perfection.
After that time, bring the skillet out from the oven and sprinkle the mozzarella cheese evenly over it.
Return it to the oven to bake for an additional 5-10 minutes, or until the cheese is melted and bubbly.
Finally, garnish with fresh basil or parsley, if desired, before serving. Voilà!