Preheat oven to 375°F. Cook spaghetti according to package directions, drain, and set aside. In a large skillet, heat olive oil over medium-high heat.
Add chicken pieces and cook until browned and cooked through, about 5-7 minutes. Remove from skillet and set aside. In the same skillet, add onion, bell pepper, garlic, diced tomatoes, and jalapeños. Cook for 4-5 minutes until softened.

Stir in smoked paprika, chili powder, salt, and pepper. Pour in chicken broth, heavy cream, and cream cheese. Cook until smooth and creamy, about 3-4 minutes. Add shredded cheddar and Monterey Jack cheeses. Stir until fully melted into a thick, gooey sauce.

Toss cooked chicken and spaghetti into the skillet until everything is coated in the cheesy sauce. Transfer the mixture to a greased baking dish. Sprinkle extra cheddar and Monterey Jack on top. Bake for 15-20 minutes until bubbly and lightly browned. Remove from oven, sprinkle with fresh parsley, and serve hot.