1. Preheat the oven to 400°F and line a large rimmed sheet pan with parchment paper or spray with cooking oil.

2. Cut the potatoes into 1-inch cubes and pat the chicken breasts dry with paper towels.

3. In a bowl, whisk together olive oil, balsamic vinegar, lemon juice, minced garlic, Italian seasoning, salt, and black pepper.

4. Place half of the marinade in a zip-top bag or shallow dish, add the chicken, and marinate for 15–30 minutes.

5. Arrange the potatoes on one side of the sheet pan and toss with the remaining marinade.

6. Place the marinated chicken breasts on the other side of the pan, spacing them evenly.

7. Roast for 25–30 minutes until potatoes are golden and chicken reaches an internal temperature of 165°F, flipping potatoes halfway through.

8. Allow the chicken to rest for 5 minutes, then sprinkle everything with chopped rosemary before serving.