Heat olive oil in a large skillet over medium-high heat.
Season the chicken thighs with salt and pepper and place them skin-side down in the skillet. Cook until the skin is crispy, about 5-7 minutes.
Flip the chicken and add the garlic to the pan. Continue to cook for another 3-4 minutes.
Add the olives, oregano, and lemon slices to the skillet. Lower the heat to medium-low, cover, and simmer for about 15 minutes, or until the chicken is cooked through.
Serve the chicken hot, garnished with additional lemon slices and fresh herbs if desired.