Combine chicken and water in a medium saucepan. Bring to a boil; cover, reduce heat, and simmer 15 minutes or until chicken is tender. Remove chicken from water; drain and finely shred. Discard water.
Coat a medium nonstick skillet with cooking spray. Place over medium-high heat until hot; add onion, and saute until crisp-tender. Add garlic and next 3 ingredients; cook 2 minutes. Stir in chicken, chili powder, and next 4 ingredients. Bring to a boil, reduce heat, and simmer 5 minutes.
Combine cornmeal, broth, and yogurt in a small bowl. Pour 2/3 cup of cornmeal mixture into chicken mixture, and simmer 5 minutes. Smooth top of mixture and arrange sliced olives over top. Drizzle remaining cornmeal mixture over top and sprinkle with cheese. Cover, reduce heat, and simmer 20 minutes. Remove from heat, and let stand, covered, 10 minutes. Sprinkle with cilantro, and serve immediately.