Preheat your oven to 425°F (220°C). Line a large baking sheet with parchment paper.
In a medium bowl, whisk together ¼ cup fresh lemon juice, 4 cloves minced garlic, 1 teaspoon dried oregano, 1 teaspoon salt, ½ teaspoon black pepper, and ½ cup olive oil until combined.
Place the 1 pound halved baby potatoes, chopped red bell pepper, chopped yellow bell pepper, sliced zucchini, and cherry tomatoes directly onto the baking sheet.
Pour about half of the dressing over the vegetables and toss everything directly on the pan until evenly coated. Spread the vegetables into an even layer.
Add the 2 pounds boneless, skinless chicken thighs on top of the vegetables. Spoon the remaining dressing over the chicken.
Bake for 35 to 40 minutes, until the chicken is cooked through and the potatoes are tender. For extra color, broil for 2 to 3 minutes at the end. Scatter the ½ cup Kalamata olives and 6 ounces feta cheese around the pan.
Spoon some of the pan juices over everything and sprinkle with 2 tablespoons chopped fresh parsley before serving.