Preheat the oven to 350 degrees F.
Cook the spaghetti noodles to al dente. Once cooked, rinse with cold water
In a medium bowl, mix together the egg, Parmesan cheese, ½ cup mozzarella cheese, basil, oregano, rosemary, garlic powder, and salt.
In a large bowl, stir together the noodles with the egg/cheese mixture and then place into a greased 9x13" baking dish.
In a medium bowl, stir together the marinara and diced tomatoes.
Evenly distribute meatballs on top of spaghetti noodles.
Top with marinara/tomato mixture, and then sprinkle with remaining mozzarella cheese.
Bake in preheated oven for 30 minutes, until cheese is melted and golden brown.