Preheat the oven to 400°F (200°C).
In a medium saucepan, combine the rinsed quinoa and chicken broth. Bring to a boil over medium-high heat, then reduce to a simmer, cover, and cook for 15 minutes or until the liquid is absorbed and quinoa is fluffy. Remove from heat and set aside.
While the quinoa cooks, in a small bowl, mix together the oregano, garlic powder, salt, and black pepper.
Pat the chicken breasts dry with paper towels. Rub both sides of each chicken breast with 1 tablespoon of olive oil, then sprinkle the seasoning mixture evenly over them.
Heat the remaining 1 tablespoon of olive oil in a large oven-safe skillet over medium-high heat. Add the chicken breasts and sear for 3-4 minutes on each side until golden brown.
Add the minced garlic to the skillet and sauté for 30 seconds until fragrant.
Add the cooked quinoa to the skillet and spread it evenly around the chicken breasts.
Scatter the cherry tomatoes over the quinoa and drizzle the lemon juice and lemon zest over the entire dish.
Transfer the skillet to the preheated oven and bake for 12-15 minutes, or until the chicken reaches an internal temperature of 165°F (74°C).
Remove the skillet from the oven and sprinkle the crumbled feta cheese and chopped parsley over the top.
Let the dish rest for 5 minutes before serving.