Bring a large pot of salted water to a boil. Cook the pasta according to the instructions on the package until just tender. Drain and rinse under cold water to halt the cooking process. Set aside to cool completely.
Meanwhile, in a skillet set over medium heat, cook the ground beef, stirring frequently, until it is no longer pink. Discard excess grease. Stir in the taco seasoning along with a few tablespoons of water, mixing until the meat is well coated. Remove from heat and allow to cool slightly.
In a separate bowl, whisk together sour cream, salsa, and ranch or mayonnaise until smooth. Add salt and pepper as needed to enhance the flavor.
In a large mixing bowl, combine the cooled pasta, seasoned beef, black beans, corn, cherry tomatoes, red onion, and shredded cheese. Pour the prepared dressing over the ingredients and toss gently until everything is evenly coated.
Cover the bowl and place it in the refrigerator for a minimum of 30 minutes to allow the flavors to meld.
Right before serving, gently fold in the chopped romaine lettuce if using, and scatter the crushed tortilla chips on top for added crunch. Serve chilled or at room temperature.