1. Preheat oven to 350ºF. Place chicken on a rimmed, foil-lined baking sheet and surround with red onion wedges. Drizzle with olive oil and sprinkle lightly with salt and pepper. Bake 20 minutes, until onions are softened and chicken is cooked through (cut to test). Let cool 10 minutes on baking sheet, then transfer chicken to cutting board and cut into half-inch cubes. Coarsely chop onion. Transfer chicken and onion to a large bowl and let cool to room temperature. Stir in roasted peppers.
2. In a small bowl, combine sour cream, mayonnaise, chipotles, adobo sauce and lime juice; stir to combine. Pour dressing over chicken mixture and toss to coat evenly. Sprinkle salad with cilantro and serve.