The day before you want to make the stuffing, bake the corn bread mix according to package directions, remove it from the pan, cover lightly with a cloth, and leave it to dry overnight. Tear the bread into pieces and leave it out overnight to dry.
About 1/2 hour before serving, preheat an oven to 350 degrees F (175 degrees C), and grease a 1 1/2-quart baking dish.
Place the sausage into a skillet over medium heat, and cook and stir the sausage, breaking it up as it cooks, until the meat is browned, 8 to 10 minutes. Stir in the celery and onion, and cook until the onion is translucent, stirring occasionally, about 8 minutes. Stir in the sage.
Tear up and crumble the corn bread into a large bowl. Break the bread apart into 1/2-inch pieces, and lightly mix it with the corn bread. Pour in the melted butter, stir to combine, and lightly mix in the sausage mixture.
Whisk the chicken broth with the eggs, and stir into the corn bread mixture. Place the stuffing into the prepared baking dish, cover with foil, and bake in the preheated oven until the stuffing is cooked through and hot, about 30 minutes. Uncover the dish and return to the oven to bake until the top is lightly browned, about 10 more minutes.