In a large nonstick skillet coated with cooking spray, cook chicken until no longer pink. Add the broth, water, vegetables and seasonings. Bring to a boil. Reduce heat; simmer, uncovered, for 30 minutes or until vegetables are tender., Meanwhile, for dumplings, in a large bowl, beat the egg whites and cottage cheese until blended. Add water and salt. Stir in the flour and mix well., Bring soup to a boil. Drop dumplings by tablespoonfuls onto the boiling soup. Reduce heat; cover and simmer for 15 minutes or until a toothpick inserted in dumplings comes out clean (do not lift cover while simmering).