Pour water and white wine into a baking dish. Add the instant chicken broth powder and stir. Add the quartered onion, crushed garlic, and halved cherry tomatoes.
Coat chicken legs lightly with olive oil, then rub with salt, pepper, paprika powder, and oregano. Place in the dish with the broth mixture. Add olives if desired.
Bake at 175°C (347°F) for 50 minutes, basting with broth every 15 minutes. Flip the chicken legs halfway through at about 25 minutes if desired. Finish with the skin facing upwards for the last 10 minutes to crisp the exterior.
Check that the chicken has reached 74°C (165°F) in the thickest part of the thigh. Serve with baked potatoes or fries.