Marinate chicken. Combine chicken thighs with olive oil, lemon juice, paprika, coriander, lemon zest, salt, pepper, and turmeric, tossing to coat. Let sit for at least 1 hour or overnight.
Meanwhile, make olive walnut vinaigrette. Combine sliced olives with chopped walnuts, parsley, basil, garlic, extra virgin olive oil, and sherry vinegar in a medium bowl. Season with salt and pepper and let sit for 30 minutes.
Preheat oven to 425 degrees F.
Pour ½ cup chicken stock and 3 sprigs thyme in bottom of a sheet pan. Place marinated chicken directly on top and roast for 40-45 minutes or until golden brown and the juices run clear. Let rest for 10 minutes.
Meanwhile, roast potatoes. Toss halved potatoes with olive oil, garlic powder, salt, and pepper. Lay on a sheet pan and roast for 30-35 minutes or until tender. Sprinkle parmesan on top and toss together.
Arrange potatoes and chicken on a serving platter. Spoon olive walnut vinaigrette on top and serve with extra vinaigrette on the side.