Preheat the oven at 350f
Heat a large oven-safe skillet, add oil and the chicken thighs, sprinkle with sea salt and pepper to taste - sear until golden on both sides. Set chicken aside on a plate.
In the same skillet, add the sliced onions, chopped garlic and anchovy and sautee for about 1 minute.
Add the olives, diced tomatoes and thyme. Cover with a lid and let it simmer for about 10 minutes.
Place the chicken over the sauce in your skillet, cover with a lid and bake at 350f, for about 50 minutes, or just until the chicken is cooked through.
Sprinkle with fresh thyme and serve hot.