Preheat oven to 425°F. Whisk the marinade ingredients together in a large bowl: olive oil, lemon zest, lemon juice, garlic, oregano, salt, and pepper. Scoop 2 tablespoons of the marinade out into a medium bowl and set aside.
Place the chicken into the large bowl and toss so that it's coated in the marinade, and let it sit at room temperature while you prepare the vegetables.
Slice the potatoes in half, or quarter them if they're larger, and place them directly onto a very large baking sheet. NOTE: If you don't own a very large baking sheet, use 2 medium baking sheets instead.
Roast the potatoes for 5 minutes. While the potatoes are roasting, place the tomatoes, green beans and onion into the medium bowl with the marinade and toss to combine.
Once the 5 minutes is up, remove the baking sheet from the oven and add the remaining vegetables and toss. Use kitchen tongs to nestle the chicken thighs into the vegetables smooth side up, trying not to have the ingredients overlap too much.
Bake for 20 minutes. Then, remove from the oven, sprinkle feta overtop, and place back into the oven for 5 minutes. Sprinkle with fresh herbs and enjoy!