Fill a large pot with water and season generously with kosher salt. Bring it to a boil, then add the rotini pasta. Cook until al dente, following the timing on the package. Once cooked, drain the pasta and rinse it under cold water to stop the cooking. Let it drain well, then transfer it to a large mixing or serving bowl.

Add the diced avocado, black beans, corn, cherry tomatoes, red onion, chopped cilantro, and jalapeño to the bowl with the pasta. Gently toss everything together until just combined, taking care not to break up the avocado too much.

In a separate medium bowl, whisk together the mayonnaise, sour cream, whole milk, lime juice, garlic powder, onion powder, chipotle powder, and kosher salt. Whisk until the dressing is smooth and creamy.

Pour the dressing over the pasta mixture. Use a large spoon or spatula to toss everything together until all the ingredients are evenly coated in the dressing.

Cover the bowl and place it in the refrigerator for at least 30 minutes to chill and let the flavors meld.