1. Preheat oven to 200°F. Arrange bread cubes in a single layer on a baking sheet and place in the oven for at least one hour to dry.
2. After bread is dried, preheat oven to 350°F.
3. Heat olive oil in a large skillet over medium-high heat. Add yellow onions and sausage. Cook until the sausage is no longer pink, crumbling with a wooden spoon.
4. In a large bowl, combine the sausage mixture with cubed bread pieces. Wipe the skillet with a paper towel and turn heat to medium.
5. Melt butter. Add chopped celery, green onion, sage, marjoram, parsley, and ground nutmeg. Cook, stirring frequently until the celery is soft, about 5 minutes.
6. Toss bread mixture with the butter mixture. Season with salt and pepper. Pour in chicken broth and toss again.
7. Lightly coat a 9 x 13-inch baking dish with cooking spray. Transfer the stuffing to the baking dish and bake 20 to 25 minutes or until the stuffing is heated through and a light crust forms on top.