Cut chicken breasts into bite-sized pieces, about ¾" cubes, and set aside.
Chop broccoli into florets, halving larger pieces if necessary.
Bring a pot of water to a boil, add ½ teaspoon of salt, and cook penne pasta over medium heat until al dente.
Add the broccoli to the pasta water in the last 4 minutes of cooking.
Once the broccoli is tender and vibrant green, remove and set aside.
Reserve ½ cup of pasta water, then drain the pasta.
In a deep skillet, melt olive oil and butter over medium heat.
Add chicken, seasoning with salt, pepper, garlic powder, paprika, and Italian seasoning.
Cook until browned, then remove and set aside.
In the same skillet, sauté minced garlic for 3 minutes.
Add cream cheese and stir until melted.
Whisk together milk and cornstarch, then slowly pour into the skillet, stirring often until the sauce thickens.
Add pasta water gradually if the sauce becomes too thick, then stir in cooked pasta, chicken, and broccoli.
Mix gently to coat, and garnish with Parmesan, chopped parsley, or toasted breadcrumbs.