Place, cut-sides down, in large microwaveable dish; cover. Microwave on HIGH 10 min. Wrap kitchen towel around one of the squash halves, then squeeze squash. If squash gives slightly, it is cooked through. Cool squash. Use fork to remove strands of squash from each half; set aside.
Mix pineapple, sugar, gingerroot and nutmeg in medium saucepan. Bring to boil on medium heat, stirring frequently. Cook until sugar is dissolved, stirring frequently.