Make macaroni and cheese according to packet instructions.
Heat 2 tablespoons olive oil in medium-sized saucepan. Fry onions until caramelised, add ham and bacon, fry until golden brown.
Add sour cream, stir together until all mixed. Reduce heat by a quarter. Add macaroni and cheese, and half the grated cheese and mix well until all cheese is melted. Remove from heat.
Add roughly broken corn chips to macaroni and cheese; mix well.
Serve onto 4 plates, garnish with any leftover crushed corn chips and grated cheese.