Preheat your oven to 400°F (200°C). Grease a baking dish or line it with parchment paper.
In a small bowl, whisk together honey, Dijon mustard, olive oil, garlic powder, salt, and black pepper to create the marinade.
Place the chicken breasts in the baking dish and pour the honey mustard marinade over them, ensuring they are well coated. Set aside to marinate for about 10 minutes.
While the chicken is marinating, bring a medium saucepan of salted water to a boil. Add the halved baby potatoes and cook for about 15 minutes or until just tender. Drain the water and set aside.
In a large skillet, heat a tablespoon of olive oil over medium heat. Add the cooked potatoes, season with thyme, and sauté for about 5 minutes, until slightly golden.
Add the drained green beans to the skillet and cook for an additional 5 minutes until heated through. Season with salt and pepper to taste.
While the beans and potatoes are cooking, place the marinated chicken in the preheated oven. Bake for about 25-30 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F (75°C).
Once cooked, remove the chicken from the oven and let it rest for a few minutes. Slice the chicken and serve it with the beans and potatoes. Garnish with fresh parsley if desired.