Bring a large pot of salted water to a boil. Cook pasta according to package directions, just to al dente. Drain and rinse under cold water until pasta is no longer hot to the touch. Add to a large bowl.
16 ounces rotini pasta
While the pasta is cooking, slice, cube, or shred the cooked chicken, halve tomatoes, and chop the bell pepper.
To make the dressing, add all of the ingredients to a food processor or blender and purée until smooth. Taste and add more salsa or seasoning as desired. If the dressing is too thick, add water 1 tablespoon at a time until it thins out.
1/3 cup mayonnaise, 1/4 cup sour cream, 1 large avocado, 1/4 cup salsa, 2 tablespoons lime juice, 2 teaspoons taco seasoning
Pour half the dressing over the pasta and mix well. Add the chicken, tomatoes, bell pepper, cheese, onion, cilantro, and remaining dressing and stir to evenly coat the ingredients.
1 cup shredded cheddar cheese, 1/2 cup diced red onion, 1/4 cup chopped fresh cilantro
Serve immediately or cover and chill until ready to eat. Enjoy within 3 days.