Cook the pasta according to package instructions until al dente.
Grill the corn until slightly charred, or use canned corn after draining.
In a large bowl, combine the cooled pasta, corn, cherry tomatoes, red onion, and cilantro.
In a separate bowl, whisk together the mayonnaise, sour cream, chili powder, salt, and pepper.
Pour the dressing over the pasta mixture and toss until well coated.
Fold in the cotija cheese gently.
Chill the salad for at least 30 minutes before serving.
Adjust seasoning if necessary and serve.