Whisk olive oil, lemon juice, oregano, garlic, salt, and pepper in a bowl. Add the chicken and toss to coat. Let it marinate for at least 15 minutes.
Combine rinsed quinoa and chicken broth in a small saucepan. Bring to a boil, then reduce heat to low and cover. Simmer for 15 minutes or until liquid is absorbed. Remove from heat and let sit covered for 5 minutes. Fluff with a fork.
Heat the remaining olive oil in a large skillet. Add the chicken and cook for 8 to 10 minutes. Turn occasionally until the internal temperature reaches 74°C (165°F). The exterior should be golden brown.
Prepare the vegetable components by dicing the cucumber, halving the tomatoes, and slicing the red onion.
Divide the cooked quinoa equally into four serving bowls.
Distribute the grilled chicken, tomatoes, cucumber, red onion, and olives evenly across the bowls.
Top each bowl with 30g of tzatziki, 15g of hummus, and 25g of crumbled feta cheese.
Serve immediately or store in airtight containers for up to 4 days.