Bring a large pot of water to a boil and add salt. Cook the spaghetti according to package instructions until al dente, about 8–10 minutes, then drain and set aside.

Heat olive oil in a large skillet over medium heat. Season chicken breasts with paprika, Italian seasoning, salt, and pepper. Cook for 5–7 minutes until golden brown and cooked through, then transfer to a plate to rest.

In the same skillet, reduce heat and add butter. Once melted, add chopped onion and sauté for 3–4 minutes until translucent. Then add minced garlic and cook for another 30 seconds.

Pour in chicken broth and heavy cream, bringing to a gentle simmer. Stir occasionally for about 5 minutes, until the sauce thickens slightly.

Return cooked spaghetti and sliced chicken to the skillet, gently tossing to coat everything in the sauce.

Sprinkle shredded Monterey Jack cheese over the top, cover, and let sit for 2–3 minutes over low heat until the cheese melts.

Garnish with freshly chopped parsley before serving hot in bowls.