Preheat the oven to 350°F.
In an oven-safe pan with high sides (I use a wide dutch oven pan), add 2 tablespoons of avocado oil. Heat on a medium flame until slightly sizzly.
Pat the chicken thighs dry with paper towel and sprinkle both sides of the with 1 teaspoon salt total.
Place half of the chicken thighs, skin side down, into the hot oil. Cook for about 5 minutes or until the skin easily pulls away from the pan and is a golden yellow color. Turn the chicken over and cook for 1 minute. Transfer to a plate.
Repeat the chicken cooking process in Step 3 with the remaining 3 chicken thighs. Place chicken thighs onto the plate with the other pieces from before.
The pot should still be hot with leftover oil. To the pot, add the sliced onion and garlic. Cook 3 minutes until onions are beginning to become translucent.
Next, add 1 tablespoon oil, tomatoes, green olives and black olives and mix to combine. Cook for 4-5 minutes until the tomato juices appear. Sprinkle with 1 teaspoon salt, chopped thyme and sugar. Cook for another 2 minutes.
Carefully place chicken thighs back into the pan and spoon the hot tomato-olive liquid over each chicken thigh so they’re coated in flavor.
Sprinkle ½ teaspoon salt over the entire pan of chicken along with black pepper.
Cover the pan with an oven-safe lid (or aluminum foil) and bake for 35 minutes.
Uncover at the 30 minute mark, baste with the tomato liquid and cook at 425°F for 15 minutes.
Allow chicken to cool 5-10 minutes before serving. Garnish with fresh parsley.