Heat the olive oil in a large pot over medium heat. Add the chicken pieces and cook until lightly browned on all sides.
Stir in the onion and garlic. Cook for two minutes until the onion softens.
Pour in the chicken broth, orzo, lemon juice, lemon zest, oregano, salt, and pepper. Bring the mixture to a gentle boil, then reduce the heat to low.
Cover and simmer for 10 to 12 minutes, stirring once halfway through, until the orzo is tender and most of the liquid is absorbed.
Remove the pot from the heat. Stir in the feta cheese, olives, and parsley until evenly mixed.