Heat oven to 425° F.
Lightly coat a 13-by-9-inch baking dish with vegetable cooking spray. Sprinkle the chicken breasts with the garlic, cayenne, and lime zest; set aside. Place the rice in the baking dish.
Combine the chicken stock, coconut milk, cilantro, salt, and lime juice and pour onto the rice. Arrange the chicken on top of the rice. Cover with foil and bake 25 to 30 minutes or until the rice is tender and the chicken is cooked through.
Remove the foil, sprinkle the coconut on top, and cook 5 minutes more or until the coconut is browned.
Make-Ahead: The recipe can be made up to 1 day ahead. Cover with foil and refrigerate. Reheat, covered, in a 325° F oven for 20 minutes or until a knife inserted into the chicken comes out warm.