Heat oil in a Dutch oven over medium heat. Add the chicken pieces and season with salt and pepper. Brown the chicken for about 5 minutes, stirring a few times to make sure all sides get some color.
Add the butter and onions and sauté the onions for another 5 minutes. Then, add the rest of the veggies to cook for another 5-7 minutes, stirring occasionally.
Reduce the heat to low and place the cover on the pot. Simmer for 20–25 minutes. Once your chicken thigh stew is done, season to taste with salt and pepper and garnish with your greens. Enjoy!