Begin by bringing a large pot of salted water to a boil over high heat. Once boiling, add the small shell pasta and cook according to package instructions, typically around 8-10 minutes, until al dente. Drain the pasta in a colander and rinse it under cold water to stop the cooking process. Set it aside to cool completely.

In a large mixing bowl, combine the drained whole kernel corn, zesty Rotel, and finely chopped green onions. Stir the mixture gently to ensure the corn and tomatoes are evenly distributed.

In a separate bowl, whisk together a generous amount of mayonnaise and sour cream until the mixture is smooth and creamy, around 1-2 minutes.

Pour the prepared dressing into the corn mixture and fold gently with a spatula until all the ingredients are well-coated.

Fold in the shredded cheddar cheese gently, then add the cooled pasta to the bowl and mix carefully to combine.

Once combined, cover the salad with plastic wrap or a lid and refrigerate it for at least 1-2 hours.