Preheat oven to 350℉.
Bring a large pot of water with 2 teaspoons chicken bouillon to a boil over high heat.
When water comes to a boil, add spaghetti and cook just until al dente. Drain off water, reserving 1 cup.
While the pasta is cooking, in a large bowl mix together; shredded chicken, cream of mushroom soup, half the grated cheddar cheese, diced green pepper, diced onion, pimentos, seasoned salt, Kosher salt, pepper and cayenne.
When noodles are cooked and drained add them to the mixture along with a cup of the pasta cooking water.
Spread mixture into a 13x9 inch oven safe casserole dish.
Top with the remaining cup of cheddar cheese.
Bake uncovered for 45 minutes or until hot and bubbly.
Cover casserole dish with foil for the last 15 minutes in the oven if the cheese begins to brown too much.