Creating Southern-Style Spicy Chicken Spaghetti Casserole is a straightforward process if you follow these simple steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Cook Spaghetti: Boil water in a large pot. Add spaghetti and cook according to package instructions until al dente. Drain and set aside.
3. Sauté Vegetables: In a skillet, heat olive oil over medium heat. Add chopped onion and minced garlic, sautéing until they are softened and fragrant.
4. Combine Ingredients: In a large mixing bowl, combine the cooked spaghetti, shredded chicken, cream of chicken soup, sour cream, diced tomatoes, sautéed onion and garlic, paprika, cayenne pepper, black pepper, and salt. Mix well until evenly coated.
5. Transfer to Casserole Dish: Pour the mixture into a greased 9×13-inch casserole dish. Spread it evenly.
6. Add Cheese and Toppings: Sprinkle shredded cheddar cheese over the top of the casserole. Then, add crushed tortilla chips for a crunchy topping.
7. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes or until it is heated through and the cheese is bubbly and golden.