Preheat oven to 425 degrees F. Spray a medium baking dish with cooking spray (I have used both a deep 9-inch by 6-inch dish and an 11-inch by 7-inch dish, and both work well).
Place chicken in the prepared dish. Sprinkle with salt, pepper, and cornstarch and toss to coat.
In a food processor or blender, puree orange zest, green onions, garlic, onion, jalapeno, soy sauce, vinegar, olive oil, brown sugar, thyme, cloves, nutmeg, and allspice. Pour sauce over chicken and stir to combine.
Bake, uncovered, for 20 minutes. Stir, return to the oven for 5-10 more minutes, or until chicken is cooked through and sauce has thickened.
Remove from oven. Garnish with sliced green onions just before serving.