Cook spaghetti according to package instructions until al dente. Drain and set aside.
In a large mixing bowl, combine the shredded chicken, cream cheese, sour cream, cheddar cheese, mozzarella cheese, diced tomatoes, green onions, garlic powder, onion powder, paprika, black pepper, and salt. Mix until well combined.
Gently fold in the cooked spaghetti into the creamy mixture until the spaghetti is well coated.
Grease a 9x13 inch baking dish and pour the spaghetti mixture into the dish, spreading it evenly.
In a small bowl, mix the breadcrumbs with a drizzle of olive oil (or melted butter) to create a light coating. Sprinkle the breadcrumb mixture evenly over the top of the spaghetti bake.
Bake in the preheated oven for about 25-30 minutes, or until the top is golden and bubbly.
Remove from the oven and let it cool for about 5 minutes before serving.
Notes
Serve warm directly from the baking dish, garnished with extra chopped green onions or a sprinkle of paprika for color.