Cut root end from fennel. Measure 1/4 cup fennel sprigs. Slice bulb thinly.
Brown chicken in oil in large skillet; remove to plate.
Drain all but 1 tablespoon drippings from skillet. Add fennel, onion and garlic; cook until lightly browned. Add tomatoes, water, salt, pepper and fennel sprigs. Bring to boiling. Return chicken to skillet; simmer, covered, until chicken is tender, no longer pink near bone, 30 minutes. Add olives; heat through.