Arrange bread in a single layer on a baking sheet.
Bake at 350 for 25 minutes or until golden.
Place bread in a large bowl.
Heat a large skillet over medium heat.
Add oil to pan; swirl to coat.
Add celery and next 6 ingredients (through salt) to pan; cook 15 minutes or until vegetables are tender, stirring occasionally.
Add celery mixture, chestnuts, and raisins to bread; toss well.
Combine chicken broth and egg, stirring with a whisk.
Add broth mixture to bread mixture, tossing gently to combine. Spoon bread mixture into a 13 x 9-inch glass or ceramic baking dish coated with cooking spray.
Bake at 350 for 50 minutes or until top is lightly browned.