In a medium skillet cook onion in 1 tbsp butter over medium heat about 5 minutes or until tender. Remove from heat and set aside.
In a bowl whisk together eggs, milk, 1/2 tsp salt, 1/4 t black pepper, and crushed red pepper.
Stir in chicken, monterey jack cheese, artichokes, spinach, tomatoes, half the parmesan, cooked pasta and onion. Transfer to a 3 qt baking dish.
Bake covered for 20 minutes.
In a small bowl combine the remaining parmesan, bread crumbs, paprika, and melted butter. Sprinkle mixture over pasta, bake uncovered for 10 minutes more or until golden.