In a medium mixing bowl, whisk together the olive oil, dried oregano, garlic powder, salt, and freshly ground black pepper. Add the chicken breasts to the bowl, ensuring they are fully coated in the marinade. Cover and let marinate for at least 30 minutes (or up to 2 hours in the refrigerator for more flavor).
In a medium saucepan, combine the rinsed quinoa and vegetable broth. Place the saucepan over medium-high heat and bring to a rolling boil. Once boiling, reduce the heat to low, cover with a lid, and let simmer for about 15 minutes, or until the quinoa is tender and the liquid has been absorbed. Remove from heat and let it sit, covered, for an additional 5 minutes. Fluff the quinoa with a fork and set aside.
Preheat a grill or a nonstick skillet over medium-high heat. Grill the marinated chicken for approximately 6-7 minutes per side, or until fully cooked and the internal temperature reaches 165°F (75°C). Once cooked, remove the chicken from the grill and let it rest for about 5 minutes before slicing into thin strips.
In a large mixing bowl, add the halved cherry tomatoes, diced cucumber, thinly sliced red onion, halved Kalamata olives, and chopped parsley. Drizzle the mixture with fresh lemon juice and red wine vinegar (if using). Gently toss the ingredients to combine.
To assemble each power bowl, start with a generous scoop of quinoa as the base. Add a layer of sliced grilled chicken on top, followed by a portion of the salad mixture. Sprinkle crumbled feta cheese over each bowl and finish with a drizzle of tzatziki sauce for a refreshing touch.
For an extra burst of flavor, garnish with fresh lemon zest. Serve immediately and enjoy your vibrant Greek chicken power bowls!
Notes
For extra flavor, let the chicken marinate longer.