1. Bring a large pot of salted water to a boil. Add spaghetti and cook until al dente. Drain and reserve ½ cup of pasta water.

2. Cut chicken into bite-sized pieces. Season with salt, pepper, and Italian seasoning.

3. In a large skillet, heat olive oil over medium-high heat. Sear chicken until golden and fully cooked, about 7–8 minutes. Remove and set aside.

4. In the same skillet, reduce heat to medium. Add diced onion and sauté until soft, about 4–5 minutes.

5. Stir in garlic and cook for 30 seconds, until fragrant.

6. Deglaze the skillet with chicken broth, scraping up browned bits. Let it simmer for 2–3 minutes.

7. Lower heat and stir in Monterey Jack cheese gradually until melted and creamy.

8. Add cooked spaghetti and chicken to the skillet. Toss everything together, adding reserved pasta water as needed to loosen the sauce.

9. Sprinkle in crushed red pepper flakes if using. Adjust seasoning to taste.

10. Garnish with fresh parsley and serve hot.