Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Cut the Yukon gold potato into 1-inch cubes and trim the ends off the green beans.
In a small bowl, whisk together the extra virgin olive oil, fresh lemon juice, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken breast, potato cubes, and green beans on the prepared baking sheet.
Drizzle the lemon-herb marinade over the chicken and vegetables, tossing well to ensure every piece is thoroughly coated.
Spread the ingredients out into a single layer to ensure even roasting.
Roast in the center of the oven for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are golden and tender.
Let the chicken rest for 5 minutes before slicing and serving alongside the roasted potatoes and beans.