In a large pot, bring salted water to a boil. Add the macaroni and cook until al dente. Drain the macaroni, reserving about 1/2 cup of the cooking water.
Meanwhile, heat a pan with a drizzle of oil over medium heat. Add the onion and sausage meat, breaking it up with a wooden spoon, and cook until well browned and the onion is translucent.
Stir in the corn, green onions, and shredded cheddar cheese. Add some of the reserved pasta cooking water to achieve a creamy consistency. Mix well until the cheese is melted and the ingredients are combined.
Season with salt and pepper to taste. Mix again and serve hot.