Preheat oven to 375°.
Arrange chopped chestnuts and bread cubes in a single layer on a jelly roll pan. Bake at 375° for 10 minutes or until lightly browned.
Cook sausage in a large nonstick skillet over medium-high heat 4 minutes or until browned, stirring to crumble. Add onion and celery; sauté 6 minutes or until tender. Add broth, scraping pan to loosen browned bits.
Combine bread mixture, sausage mixture, sage, thyme, salt, and pepper, tossing to combine. Spoon into a 13 x 9-inch baking pan coated with cooking spray; cover with foil. Bake at 375° for 20 minutes. Uncover and bake an additional 10 minutes or until golden brown.