Coat a 9-inch x 13-inch baking dish with PAM Cooking Spray.
Cut French bread into 1-inch cubes, enough to fill the 9-inch x 13-inch baking dish.
In a large bowl, whisk together eggs, milk, vanilla, pumpkin puree and pumpkin pie spice until well combined. Pour over bread and push down with a spoon or your hands until it's all soaked and mostly covered. Cover with plastic wrap and refrigerate overnight or at least a few hours.
In the morning, preheat oven to 350 degrees, uncover and sprinkle the top with nuts and brown sugar. Bake for 35-45 minutes or golden brown and no longer wet. Meanwhile, prepare maple glaze by whisking the powdered sugar, maple syrup and heavy cream together, until smooth.
Remove from the oven and pour over the maple glaze while still warm. Serve immediately. Store leftovers in the refrigerator covered for up to a couple days.