1. Preheat oven to 425°.
2. Pierce potatoes several times with a fork; place on a foil-lined baking sheet. Bake at 425° for 1 hour or until tender. Cool slightly; peel and mash in a large bowl. Stir in milk and next 4 ingredients (through cheese).
3. Cook pasta according to package directions, omitting salt and fat; drain. Add pasta to sweet potato mixture; set aside.
4. Preheat broiler to high.
5. Heat a large ovenproof skillet over medium heat. Add oil; swirl to coat. Add chorizo to pan; cook 4 minutes or until browned, stirring to crumble. Place chorizo in a small bowl. Wipe pan clean. Spoon sweet potato mixture into pan; sprinkle evenly with chorizo. Broil 2 minutes or until lightly browned and crisp. Sprinkle with onions and cilantro.