In a small bowl, combine the Italian seasoning, paprika, salt, and black pepper. Pat the chicken dry, then season both sides evenly with the mixture.
Heat a large, deep skillet over medium heat. Add 1 tablespoon avocado oil. Once hot, add the chicken and cook for 3–5 minutes per side, or until golden and the thickest part reaches an internal temperature of 165°F (74°C). Transfer the chicken to a plate and allow it to rest.
Reduce the heat to medium-low. Add the remaining tablespoon of avocado oil and the butter to the same pan.
Add the diced onion with a small pinch of salt. Cook for about 3 minutes, stirring occasionally, until the onion begins to soften and turn translucent.
Stir in the minced garlic and cook for about 1 minute, just until fragrant.
Pour in the chicken broth and scrape the bottom of the pan to loosen the flavorful browned bits. Bring the broth to a gentle boil.
Add the dry penne and stir well, making sure the pasta is mostly submerged in the broth. Cover and cook for approximately 10 minutes, or according to the pasta package directions, until al dente. Stir occasionally to prevent sticking and check the liquid level as it cooks.
Turn off the heat. Add the Parmesan cheese, heavy cream, and chopped parsley. Stir until the cheese has melted and the sauce becomes smooth and creamy. Season with additional salt and pepper if needed.
Slice the rested chicken into strips and return it to the skillet. Gently toss everything together until the chicken is coated in the creamy sauce.
Serve your Garlic Parmesan Chicken Pasta warm, with extra Parmesan and parsley if desired.