Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Dice the gold potato into small 1/2-inch cubes to ensure they cook through at the same rate as the chicken.
Place the chicken breast on one side of the pan and the diced potatoes on the other side.
Drizzle 0.5 tablespoons of olive oil over the chicken and potatoes, then season evenly with dried oregano, garlic powder, sea salt, and black pepper.
Toss the potatoes to coat and roast the pan in the oven for 15 minutes.
While the chicken and potatoes roast, trim the ends off the green beans and finely mince the fresh garlic clove.
Remove the sheet pan from the oven, move the ingredients slightly to make room in the center, and add the green beans.
Drizzle the remaining 0.25 tablespoons of olive oil and the minced garlic over the green beans, tossing them lightly on the pan.
Return the pan to the oven and roast for an additional 10 to 12 minutes until the chicken is cooked through and the potatoes are golden.
Finish by squeezing the fresh lemon juice over the entire pan before serving to brighten all the flavors.