Cook the pasta. Bring a large pot of salted water to a boil. Cook the pasta according to package directions until al dente. Drain and rinse under cool water to stop the cooking. Shake off excess water and transfer to a large bowl.

Make the avocado ranch. In a blender or food processor, combine the avocado, Greek yogurt or mayo, buttermilk or milk, ranch seasoning, lime juice, olive oil, and garlic. Blend until smooth and creamy. Adjust thickness with more buttermilk or milk as needed.

Season the dressing. Taste and season with salt and black pepper. If you like extra tang, add a splash more lime. If it tastes too bold, balance with a teaspoon of honey or a bit more yogurt.

Prep the mix-ins. Add the chicken, tomatoes, corn, red onion, cucumber, bell pepper, and herbs to the bowl with the cooled pasta.

Combine. Pour about two-thirds of the dressing over the salad. Toss gently with a spatula until everything is coated. Add the remaining dressing if you like it creamier.

Add cheese (optional). Fold in shredded cheddar or Monterey Jack. Taste and adjust salt and pepper.

Chill briefly. For best flavor, cover and refrigerate for 20–30 minutes to let the flavors mingle.

Serve. Give it a final toss. If it thickened in the fridge, loosen with a splash of milk or a squeeze of lime. Garnish with extra herbs.