Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Dice the gold potatoes into small 1/2-inch cubes and trim the ends of the green beans.
Cut the chicken breast into 1-inch bite-sized pieces for even cooking.
In a large bowl, whisk together the olive oil, lemon juice, lemon zest, oregano, garlic powder, sea salt, and black pepper.
Add the chicken, potatoes, and green beans to the bowl and toss thoroughly until everything is well-coated in the herb marinade.
Spread the mixture in a single layer on the prepared sheet pan, ensuring pieces are not overcrowded.
Roast for 20-25 minutes, tossing halfway through, until the potatoes are tender and the chicken is cooked through to an internal temperature of 165°F.
Remove from the oven and serve immediately while the potatoes are still crispy.