1. Preheat oven to 400 degrees Fahrenheit.
2. Heat oil over medium-high heat in a frying pan (see note). Add the onions and cook, stirring every 30 seconds for about 15 minutes until the onions are dark and caramelized.
3. Spray a pan with nonstick spray. Add the rice to the pan. Mix in the salt, pepper, and half of the onions. Pour in the water. Place the chicken on top of the rice and top with remaining onions.
4. Cover the pan with foil. Cook for one hour, then uncover and cook for another 25 to 30 minutes.
If you have a Dutch oven or stove-to-oven pot, make the onions in the pot first, remove about half the onions, and then follow remaining instructions as above.