Heat oven to 400 degrees. Halve squash and place, cut side up, on a large baking sheet. Bake 50 minutes or until tender. Scoop out squash meat and transfer squash meat to a large bowl. In a saucepan, melt the butter over medium low heat. Add onion and nutmeg, then saute until onion is tender. Transfer to bowl with squash. Add chicken broth and syrup. Puree mixture in a processor or blender until smooth. Season with salt and pepper. Return puree to saucepan. Stir over medium heat until heated through. Transfer to serving bowl and serve hot.