Season chicken thighs with salt, pepper, and oregano.
In a large oven-safe skillet, heat olive oil over medium-high heat. Sear the chicken thighs skin-side down until golden, about 4–5 minutes per side. Remove and set aside.
In the same skillet, sauté onion until translucent. Add garlic and cook for 1 more minute.
Stir in rice, then add chicken broth, lemon juice, and zest. Bring to a simmer.
Return chicken to the skillet, skin-side up. Cover and bake at 350°F (175°C) for 30–35 minutes, or until rice is cooked and chicken is tender.
Garnish with fresh parsley and serve warm.