Preheat oven to 350 and Spray a 9 x 13 inch casserole dish with cooking spray.
Bring a pot of water to a roiling boil. Break spaghetti noodles (TWICE- or into thirds) into the water, stir and cook until VERY al dente, a little gummy. Drain.
Meanwhile, in a big skillet, stir together canned chicken, cream of chicken soup, diced tomatoes, seasonings and 1 cup of the cheese. Add drained noodles to mixture and stir well.
Pour into greased casserole dish and spread evenly. Top with remaining cheese.
Bake at 350 degrees for 30 minutes.