Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Wash and dice the red potatoes into one-inch cubes, leaving the skin on for extra fiber and nutrients.
In a mixing bowl, toss the potato cubes with half of the olive oil, minced garlic, dried rosemary, salt, and pepper.
Spread the seasoned potatoes in a single layer on one side of the baking sheet and roast for 15 minutes.
While the potatoes are roasting, toss the trimmed green beans with the remaining olive oil and a pinch of salt.
Season the chicken breast generously on both sides with salt and pepper.
Remove the baking sheet from the oven and place the chicken breast and green beans on the empty side of the pan.
Return the pan to the oven and continue roasting for 18 to 22 minutes until the chicken reaches an internal temperature of 165°F.
Let the chicken rest for five minutes before slicing to keep it juicy, then serve alongside the golden potatoes and crisp beans.