Cook the Spaghetti: Bring a large pot of salted water to a boil and add the spaghetti. Cook according to package instructions until al dente, usually around 8-10 minutes. When done, reserve a cup of pasta water, then drain the spaghetti and set it aside in a large bowl. Make sure it doesn't stick together by tossing it lightly with a drizzle of olive oil.

Sauté the Chicken: In a large skillet, heat 2 tablespoons of olive oil over medium heat. Season the chicken breasts with paprika, Italian seasoning, salt, and pepper. Add the chicken to the hot skillet and cook for about 5-7 minutes on each side, until golden brown and fully cooked. Remove the chicken from the skillet and let it rest.

Cook the Aromatics: In the same skillet, melt 2 tablespoons of butter over medium heat. Add the finely chopped onion and sauté for about 3-4 minutes until soft. Add the minced garlic and cook for an additional 30 seconds, stirring constantly.

Create the Sauce: Pour in the chicken broth and heavy cream into the skillet, stirring well. Let this mixture simmer for about 5 minutes to thicken slightly.

Combine Chicken and Pasta: Add the cooked spaghetti and sautéed chicken back into the skillet. Toss everything together until well coated. If too thick, add reserved pasta water.

Melt the Cheese: Sprinkle shredded Monterey Jack cheese evenly over the mixture, cover, and cook on low heat for 2-3 minutes until cheese is melted.

Garnish and Serve: Once melted, sprinkle chopped parsley over the dish and serve immediately.