1. Split each sweet potato lengthwise and fluff the flesh with a fork. Scoop the chicken mixture into each cavity, then drizzle with olive oil and sprinkle with salt and pepper.
2. Return the stuffed sweet potatoes to the oven at 400°F for five to seven minutes, until heated through.
3. To serve, top each stuffed sweet potato with avocado, cilantro, and scallions. Serve immediately.