Heat olive oil in a large deep skillet or Dutch oven over medium-high heat.
Add the chicken pieces to the skillet and season with salt, black pepper, and Italian seasoning.
Cook the chicken until browned on all sides and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add the minced garlic and cook for 1 minute until fragrant, stirring constantly to avoid burning.
Add the uncooked penne pasta, chicken broth, and whole milk to the skillet. Stir to combine and bring the mixture to a boil.
Reduce heat to medium-low and simmer uncovered, stirring occasionally, until the pasta is tender and most of the liquid is absorbed, about 12-15 minutes.
Return the cooked chicken to the skillet and stir to combine with the pasta.
Add the butter and grated Parmesan cheese to the skillet. Stir until the cheese and butter are melted and the sauce is creamy.
Sprinkle crushed red pepper flakes and chopped fresh parsley over the pasta and stir gently.
Remove from heat and serve immediately.