Place first 3 ingredients in a spice or coffee grinder; process until finely ground. Combine cumin mixture, nutmeg, ginger, red pepper, and cinnamon; set aside.
Heat oil in a Dutch oven over medium heat. Add onion and salt; cover and cook 10 minutes. Add 1 teaspoon cumin mixture, sugar, and black pepper; cover and cook 15 minutes.
Preheat oven to 375°.
Add broth, and cook, uncovered, 30 minutes. Add raisins, chicken, and chickpeas; cover and bake chicken mixture at 375° for 30 minutes. Serve with couscous.
Note: Store remaining cumin mixture in an airtight container for up to 6 months.