Whisk yogurt, juice, 1/2 tablespoon garlic, the curry, 1/2 teaspoon cumin, and the ginger together in a bowl. Place in a large resealable plastic bag with chicken and seal, turning until chicken is coated. Marinate chicken, chilled, at least 1 hour or up to 2 hours.

Preheat oven to 425 degree F and lightly oil a shallow ovenproof 4-quart pan with lid.

Heat oil in a 4-quart saucepan over moderate heat; add onion and cook until softened, about 2 minutes. Add remaining 1 tablespoon garlic and 1/2 teaspoon cumin; cook, stirring, 1 minute. Stir in broth, 1/2 cup water, and the cinnamon stick; bring to boil. Stir in couscous, then immediately remove pan from heat and cover. Let stand for 5 minutes; uncover and stir in raisins and cilantro.

Toss couscous mixture with chickpeas and zucchini in prepared pan. Pour 1/2 cup water over top. Remove chicken from marinade (discard marinade) and place in a single layer over couscous. Season chicken with salt and pepper; bake, covered, in middle of oven until chicken is cooked through, 30 to 35 minutes. Sprinkle with nuts and serve with lime wedges on the side. Makes 6 to 8 servings.