Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Wash and dice the red potatoes into small 0.5-inch cubes to ensure they roast quickly and become crispy.
Trim the ends off the green beans and cut the chicken breast into uniform 1-inch bite-sized pieces.
In a small glass bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken, potatoes, and green beans onto the prepared sheet pan and pour the lemon-herb dressing over the top.
Toss the ingredients thoroughly to ensure every piece is well-coated, then spread them out into a single, even layer.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the potatoes are golden and fork-tender.
Remove the pan from the oven and garnish with a sprinkle of freshly chopped parsley before serving hot.