Heat olive oil in a large skillet over medium heat, then cook sliced turkey sausage until browned on both sides; remove and set aside.
In the same skillet, add diced chicken, onion, and garlic; season with Italian seasoning, salt, and pepper, and cook until chicken is cooked through, about 5–7 minutes.
Bring a large pot of salted water to a boil; cook pasta according to package directions until al dente, then drain and set aside.
Return browned sausage to the skillet with chicken; pour in chicken broth and heavy cream, stir, and bring to a gentle simmer over medium-low heat.
Lower heat and stir in Pepper Jack and Parmesan cheeses until melted and sauce is creamy.
Add drained pasta to the skillet and toss to coat evenly in the sauce.
Serve hot, garnished with chopped fresh parsley.