Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Dice the gold potato into uniform 1/2-inch cubes and slice the chicken breast into even 1-inch bite-sized pieces.
In a large mixing bowl, toss the chicken and potatoes with the extra virgin olive oil, dried rosemary, garlic powder, sea salt, and black pepper until every piece is well coated.
Spread the chicken and potato mixture in a single layer on the prepared baking sheet, ensuring they are not overcrowded so they roast rather than steam.
Roast in the center of the oven for 20 to 25 minutes, tossing the ingredients halfway through, until the potatoes are golden and the chicken is cooked through.
While the chicken and potatoes roast, place the green beans in a steamer basket over boiling water and steam for 5 to 7 minutes until they are vibrant and tender-crisp.
Remove the baking sheet from the oven and squeeze the fresh lemon juice over the roasted chicken and potatoes to brighten the flavors.
Plate the herb-roasted chicken and potatoes alongside the steamed green beans and serve immediately.