Melt 3 T butter in skillet and sauté the onion, pepper, celery till crisp tender--5-10 minutes. Remove from heat.
Melt 1 T butter in another skillet and add garlic and the cut up chicken. Cook and stir for several minutes until the chicken is lightly browned but do not overcook. Remove from heat and add the cooked vegetables, tomatoes, spinach, marjoram, and seasonings to taste. Set aside.
In a sauce pan, heat the remaining 1 T of butter and when it is melted, add the flour, stirring with a whisk. When blended, add the cream stirring rapidly with a whisk. When thickened and smooth, add the nutmeg. Stir this sauce into the chicken and vegetable mixture and then add parmesan cheese and mix all together.
Drop noodles into boiling salted water and cook a little less than package indicates. Drain well. (The noodles will cook further in the oven)
Mix noodles and chicken together into a large rectangular dish. Top with shredded cheese. Cover the casserole dish with foil.
Bake for 25 minutes covered with foil and then remove the foil and bake for an additional 15 to 20 minutes and then run under the broiler just before serving.