Make dressing: In a blender, combine cilantro, lime juice, and oil; season with salt and pepper. Blend until smooth.
In a large bowl, combine chicken, cabbage, bell pepper, and scallions; season with salt and pepper. In another large bowl, toss lettuce with 1/2 cup dressing. Divide among four bowls, and top with chicken mixture. Drizzle all with remaining dressing, and sprinkle with cashews.