In a bowl, mix chicken with 1/2 tsp salt, black pepper, 1 tbsp dried oregano, minced garlic, lemon zest, and 4 tbsp lemon juice.
Heat 1 1/2 tbsp olive oil in a large oven-safe pan. Sear chicken until lightly golden on both sides, then transfer to a plate.
In the same pan, sauté the onion until softened.
Add rice and stir for 1 minute. Season with 1 tbsp dried oregano, 1/3 tsp salt, and black pepper.
Pour in chicken broth and water. Stir well.
Nestle chicken back into the pan. Cover and bake at 375°F (190°C) until rice is tender and chicken is cooked through.
Rest 10 minutes. Garnish with parsley and fresh lemon zest, then serve.