Prepare gnocchi according to package directions. Drain. Cover and keep warm.
Meanwhile, place squash, cut sides down; in a microwave-safe baking dish with 2 tablespoons water. Microcook, covered, on high (100 percent power) 7 to 10 minutes; rearrange once. Let stand, covered, 5 minutes.
Sprinkle chicken with salt and pepper. In large skillet cook chicken in 1 tablespoon hot oil over medium heat 6 to 8 minutes, until no longer pink. Remove; cover, keep warm.
Scrape flesh from squash; mash. Transfer to hot skillet; stir in broth and chopped sage. Bring to boiling; simmer 1 minute. Stir in milk. Spoon into bowls. Top with chicken and gnocchi; sprinkle sage and nutmeg. Serves 4.