Season breasts with Tony Chachere's. Heat olive oil in cast iron skillet over medium high heat. Add chicken and cook until brown, about 3 minutes each side. Remove chicken from skillet and set aside.
Add sliced sausage to skillet and brown, approximately 5 minutes. Remove and set aside.
Lower heat to medium. add onions, celery, and bell pepper, and saute until onions are translucent. Return chicken and sausage to the skillet, and add garlic and water. Stir to incorporate. Reduce heat to low, cover and cook for 45 minutes. Add green onions and parsley.