Preheat your oven to 350°F and grease a 9x13 baking pan.
Place the crumbled cornbread into a very large mixing bowl.
Add the chopped celery and onions to the bread and toss to combine.
Pour the melted butter over the mixture.
Gradually add 3 cups of chicken broth, stirring until you reach a thick consistency. Add more broth only if needed.
Stir in the poultry seasoning, sage, and salt. Taste the mixture and adjust seasoning as desired.
Fold in the cooked chicken and the lightly beaten eggs until fully incorporated.
Spoon the dressing into the prepared baking pan.
Cover the pan with foil and bake for 30 minutes.
Remove the foil and bake for another 30 minutes until the top is golden brown and the center is set.