Special equipment: 5- to 6-quart slow cooker
In a 5- to 6-quart slow cooker, combine the sherry, soy sauce, brown sugar, ginger, five-spice powder, garlic and white parts of the green onions. Add the chicken thighs and toss to coat with the sherry mixture. Cover the slow cooker and cook as the manufacturer directs on low for 8 hours or on high for 4 hours. Coarsely chop the remaining green onion parts. Wrap and refrigerate until serving time. Just before serving, place the stir-fry veggies in a microwave-safe medium bowl and cook in the microwave as the package label directs. With tongs, transfer the chicken to a deep platter. Stir the veggies into the slow cooker to coat with the sauce. Spoon the veggie mixture around the chicken. Sprinkle with the reserved green onions.