Simmer water, chicken, diced onions, celery, minced parsley, bay leaf, salt and pepper in Dutch oven until chicken is tender. Remove bay leaf; discard. Remove chicken; cool. Cut into small cubes; set aside.
Add potatoes, green onions, bouillon cubes, seasoned salt and poultry seasoning to broth. Simmer 15 minutes. Add milk, macaroni, and chicken; return to simmer.
Melt butter in skillet over med heat. Add flour, stirring constantly, until mixture begins to brown. Add to soup; blend well. Let soup simmer on very low heat 20 minutes to blend flavors. Season to taste. Garnish with nutmeg and chopped parsley.