Preheat oven to 350°. Crumble chorizo into a 10-in. cast-iron or other ovenproof skillet; add corn, red onion and pepper. Cook over medium heat until meat is fully cooked, 6-8 minutes; drain. Stir in the cheeses.
Bake until bubbly, 14-16 minutes. Sprinkle with tomato and green onions. Serve with chips.