Place the chicken thighs in the slow cooker. Add the barbecue sauce, Sriracha, garlic powder, salt, and black pepper. Stir to coat the chicken evenly.
Cover and cook on low for 6 hours or on high for 3 to 4 hours until the chicken shreds easily with two forks.
While the chicken cooks, wash the sweet potatoes and pierce each one several times with a fork. Bake at 400°F for 45 to 60 minutes until soft, or microwave individually for 8 to 10 minutes until tender.
Once the chicken is done, shred it directly in the slow cooker and stir to soak up the sauce.
Slice each sweet potato open lengthwise and fluff the flesh with a fork. Spoon the shredded chicken mixture into each potato.
Top with sliced green onions and chopped cilantro before serving.