Begin by bringing a large pot of salted water to a boil. Add the small shell pasta and cook according to the package instructions, usually around 8-10 minutes, until al dente. Once cooked, drain the pasta in a colander and rinse it under cold water to stop the cooking process, allowing it to cool completely.

In a spacious mixing bowl, combine the drained whole kernel corn, zesty Rotel tomatoes, and finely chopped green onions. Gently toss everything together until well mixed, creating a colorful base for your Fiesta Corn Pasta Salad.

In a separate bowl, whisk together mayonnaise and sour cream until the mixture is smooth and well blended. Taste and adjust the seasoning if necessary.

Pour the creamy dressing over the corn mixture in the large bowl. Gently fold in the shredded cheddar cheese, then add the cooled pasta, folding everything together until incorporated.

Cover the Fiesta Corn Pasta Salad with plastic wrap and place it in the refrigerator. Let it chill for at least 1-2 hours to meld the flavors.