Butter a 13x9x2-inch baking dish. Arrange bread slices in the bottom of the dish, overlapping as necessary.
In a large mixing bowl, combine eggs, milk, half-and-half, vanilla, nutmeg and cinnamon. Slowly pour egg mixture evenly over bread. Press down lightly with large spoon. Cover and chill in the refrigerator for 2 to 24 hours.
In bowl, mix butter, brown sugar, and corn syrup. Stir in nuts. Spoon small mounds of the nut mixture over the bread in baking dish.
Place baking dish in a 15x10x1-inch baking pan to catch drips during baking. Bake, uncovered, in a 325 degree F oven 1 hour or until puffed and golden. Let stand 15 minutes.