Add chicken breasts to a saucepan (the smallest pan you can fit them in so that 2 cups of water will cover or mostly cover them). Add water, salt and pepper. Cover then bring to a boil. Once, boiling, reduce heat to low then cook for 30 minutes or until cooked through (larger, bone-in breasts may take longer).
Remove chicken from pot to cool, reserving 2 cups of broth.
Preheat oven to 350 degrees.
Combine 2 cups reserved broth, cream of chicken soup (do not prepare first) and poultry seasoning then whisk until smooth; set aside.
Sauté celery and onion in butter for 5 minutes then add to a large mixing bowl.
Shred or cut chicken into bite-sited pieces, add to bowl with vegetables then stir to combine.
Crumble cornbread into bowl with chicken and vegetables then pour in broth mixture. Gently fold to combine all ingredients. Taste for seasoning then add salt, pepper or more poultry seasoning if desired.
Spoon mixture into a 2-quart casserole dish. Bake, uncovered, for 40-45 minutes or until golden brown. All of the ingredients are cooked (and there are no raw eggs, etc) so we really just need to heat everything through and get a little color on the top.
