Preheat the oven to 400F and line a large sheet pan with parchment paper.
Combine the olive oil, smoked paprika, basil, parsley, oregano, salt, and ground black pepper in a small bowl and set aside.
Add the chicken thighs, sliced onion, tomatoes, olives, and garlic to a large bowl. Cover with the olive oil and spices and mix with tongs or clean hands until evenly coated.
Transfer the chicken and vegetables to the prepared sheet pan and spread out in one even layer. Bake until the chicken reaches an internal temperature of 165F and veggies are soft, 40-45 minutes.
