Preheat oven to 350 degrees. Spray a 9 X 13-inch baking dish lightly with nonstick cooking spray. Set aside.
Cook spaghetti according to package instructions until al dente and drain well. Return drained pasta to the pasta pot.
Add the remaining 2 tablespoons oil to the skillet. Saute the onions over medium heat, stirring often, until they begin to soften, about 5 minutes.
Add the mushrooms to the onions and continue to cook until mushrooms are soft; set aside.
In a large mixing bowl combine cream of mushrooms soup, sour cream, milk, diced tomatoes, chili sauce, cumin, coriander, chili powder, pepper, and 2 cups of the jack cheese until smooth.
Add the cooked chicken, vegetables, and the sauce to the pasta pot and fold until everything is evenly coated. Pour into prepared baking dish and sprinkle top with remaining cheese. Bake for 25-30 minutes or until heated through and bubbly. Sprinkle with parsley and serve.