Preheat the oven to 375 degrees. Spray a 9-by-13-inch baking dish with cooking spray and set it aside.
Cook the pasta according to the directions on the box.
In a large mixing bowl, combine the sauce, diced tomatoes, cream cheese, basil, parsley, oregano, garlic, onion powder, salt and pepper.
Once the pasta is done, drain it (don't rinse it) and add it to the mixing bowl and stir.
Pour half of the pasta mixture into the baking dish and then spread the sour cream over the top. Sprinkle on about half of the mozzarella, spread the remaining pasta on top, and then finish with the rest of the cheese.
Bake, uncovered, for about 20 minutes or until the top of the cheese is melted fully and slightly browned.