Dressing:
2/3 cup light sour cream
1/3 cup chopped fresh cilantro
4 teaspoons fresh lime juice
1 tablespoon minced chipotle chile, canned in adobo sauce
1 teaspoon ground cumin
1 teaspoon chili powder
1/4 teaspoon salt
Salad:
4 cups shredded romaine lettuce
2 cups chopped roasted skinless, boneless chicken breast (about 2 breast halves)
1 cup cherry tomatoes, halved
1/2 cup diced peeled avocado
1/3 cup thinly sliced red onion
1 (15-ounce) can black beans, rinsed and drained
1/2 cup frozen corn kernels, cooked and cooled
To prepare dressing, combine first 7 ingredients, stirring well.
To prepare salad, combine lettuce and remaining 6 ingredients in a large bowl. Drizzle dressing over salad; toss gently to coat. 4 servings.