In a large skillet, heat the olive oil and add the chicken, browning both sides of each piece. Saute for approximately 10 minutes. Add salt and pepper to taste.
Add the diced onion/s to the skillet and stir together with the chicken pieces for approximately 5 minutes. Add 2 cups of water and let simmer on medium high heat until the onions caramelize and create a sauce.
Simmer for approximately 30 minutes. You may need to add more water so that the sauce mixture doesn't dry out. Once the chicken is cooked through, remove and set on a plate.