Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Wash the yellow potato and dice it into 1/2-inch cubes, and trim the ends off the fresh green beans.
Cut the chicken breast into even 1-inch bite-sized pieces to ensure they roast at the same rate as the potatoes.
In a large mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, minced garlic, dried rosemary, sea salt, and black pepper.
Add the chicken pieces, diced potatoes, and green beans to the bowl, tossing thoroughly until every piece is coated in the herb marinade.
Spread the mixture in a single layer on the prepared baking sheet, making sure the ingredients are spread out and not crowded to allow for crisping.
Roast for 20 to 25 minutes, tossing the ingredients halfway through, until the chicken is cooked through and the potatoes are golden and tender.