Bring a large pot of salted water to a boil. Cook the penne according to package directions until al dente. Drain and set aside.
While the pasta cooks, heat olive oil in a large skillet over medium-high heat. Season the diced chicken with salt and pepper. Sauté the chicken pieces until golden brown and cooked through, about 6–8 minutes. Remove from the skillet and set aside.
In the same skillet, melt butter over medium heat. Add the minced garlic and sauté for about 1 minute, until fragrant. Pour in the heavy cream, stir in the Italian seasoning, and bring to a gentle simmer.
Stir in the grated Parmesan cheese and whisk until melted and the sauce is smooth and thickened slightly.
Return the cooked chicken to the pan, then add the drained penne. Toss everything together until well-coated in the creamy sauce.
Serve hot, topped with extra Parmesan cheese and chopped parsley for garnish.