Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Wash and cube the Yukon gold potatoes into bite-sized pieces, then place them in a bowl and toss with 1 teaspoon of olive oil, half the sea salt, half the black pepper, and the minced fresh rosemary.
Spread the potatoes in a single layer on the baking sheet and roast for 15 minutes to give them a head start on crisping.
While the potatoes roast, season the chicken breast evenly with the remaining sea salt, black pepper, fresh thyme, and minced garlic.
Remove the baking sheet from the oven, slide the potatoes to one side, and place the chicken breast and trimmed green beans on the other side.
Drizzle the green beans with the remaining 1 teaspoon of olive oil and toss them slightly to coat.
Return the sheet to the oven and roast for an additional 15 to 20 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender and golden.
Remove from the oven and immediately drizzle the fresh lemon juice over the chicken and vegetables, then garnish with the bright lemon zest before serving.