In a small saucepan, combine the soy sauce, sherry, chicken broth, ginger, garlic powder and green onions. Bring to a boil, and immediately remove from heat. Set aside.
Preheat your oven's broiler. Thread chicken pieces onto metal or bamboo skewers. Arrange on a broiler pan that has been coated with cooking spray. Spoon 1 or 2 tablespoons of the sauce over each chicken skewer.
Place the pan under the broiler, and broil for about 3 minutes, until browned. Remove from the oven, turn over, and spoon more sauce onto each one. Return to the oven until chicken is cooked through and nicely browned.