Slice chicken breasts into bite-sized pieces and season with Cajun seasoning and smoked paprika. Let rest for 10 minutes.

Bring a large pot of salted water to a boil and cook spaghetti for 9-11 minutes until al dente. Drain and set aside.

In a skillet, sear the chicken over medium-high heat for 6-8 minutes until browned and cooked through. Remove and set aside.

Melt butter in the skillet, add garlic and cook for 1 minute. Stir in flour and whisk for 1-2 minutes to create a roux.

Gradually whisk in milk and chicken broth. Simmer for 3-4 minutes until thickened.

Stir in cream cheese and mozzarella until melted and smooth. Adjust seasoning with salt and pepper.

Combine spaghetti and chicken with the creamy sauce in the skillet. Simmer on low for 1-2 minutes.

Transfer to a baking dish, top with remaining mozzarella, and broil for 2-3 minutes until golden.

Let cool slightly, garnish with parsley or red pepper flakes, and serve warm.