Heat olive oil in a large skillet over medium heat.
Season chicken breasts with salt, pepper, and oregano, then sear until golden on both sides.
Remove chicken from the skillet and set aside.
In the same skillet, sauté onion and garlic until softened and fragrant.
Add cherry tomatoes, olives, and chicken broth. Simmer for 5 minutes until tomatoes begin to burst.
Return chicken to the skillet, cover, and cook until chicken is fully cooked through, about 10 minutes.
Squeeze fresh lemon juice over the skillet before serving.
Garnish with parsley and serve hot with rice, quinoa, or salad.