Preheat your oven to 400°F (200°C).
Cut the sweet potato into 1/2-inch cubes and trim the green beans.
In a bowl, toss the sweet potato cubes and green beans with 1 teaspoon olive oil, salt, and pepper. Spread them evenly on a baking sheet.
Roast the vegetables in the oven for about 20-25 minutes, stirring halfway through.
While the vegetables roast, prepare the chicken. Pound the chicken breast to an even thickness for even cooking.
In a small bowl, mix together lemon juice, minced garlic, dried thyme, dried rosemary, salt, and pepper.
Coat the chicken breast with the lemon-herb mixture.
Heat a skillet over medium-high heat. Sear the chicken on each side for 3-4 minutes until a golden crust forms.
Reduce the heat and cook the chicken for an additional 4-5 minutes, or until the internal temperature reaches 165°F (74°C).
Serve the crispy lemon-herb chicken alongside the roasted sweet potatoes and green beans.