Heat olive oil in a large skillet over medium-high heat.
Season the chicken pieces with salt and black pepper.
Add the chicken to the skillet and cook for 5-6 minutes, stirring occasionally, until browned and cooked through. Remove chicken from the skillet and set aside.
Reduce heat to medium and add minced garlic to the skillet. Cook for 1 minute until fragrant, stirring constantly to prevent burning.
Pour in the chicken broth and heavy cream, stirring to combine.
Add the uncooked penne pasta to the skillet. Bring the mixture to a boil, then reduce heat to a simmer.
Cover the skillet and cook for 12-15 minutes, stirring occasionally, until the pasta is tender and most of the liquid is absorbed.
Stir in the cooked chicken, grated Parmesan cheese, crushed red pepper flakes, and butter until the cheese and butter are melted and the sauce is creamy.
Remove from heat and sprinkle chopped fresh parsley over the top before serving.