Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
In a small bowl, toss the diced gold potatoes with 1 teaspoon of olive oil, half of the dried rosemary, and a pinch of salt and pepper.
Spread the potatoes in a single layer on the prepared baking sheet and roast for 10 minutes.
While the potatoes are roasting, season the chicken breast with the remaining olive oil, lemon juice, garlic powder, remaining rosemary, salt, and pepper.
Remove the baking sheet from the oven, move the potatoes to one side, and place the chicken breast on the other side.
Return the pan to the oven and roast for an additional 18 to 22 minutes, or until the chicken is cooked through and the potatoes are golden brown.
While the chicken and potatoes finish roasting, steam the broccoli florets in a steamer basket over boiling water for 4 to 5 minutes until tender-crisp.
Plate the roasted chicken and potatoes alongside the steamed broccoli and serve immediately.