Preheat your oven to 425°F.
In a small bowl, whisk together olive oil, lemon juice, minced garlic, chopped rosemary, thyme, salt, and pepper.
Place the chicken breast on a baking tray lined with parchment paper. Brush the chicken generously with the lemon herb mixture.
Cube the sweet potato into even pieces and toss with a little olive oil, salt, and pepper. Spread on a separate baking tray.
Cut the broccoli into florets and season lightly with salt, pepper, and a drizzle of olive oil. Arrange alongside the sweet potatoes.
Roast the sweet potatoes and broccoli in the oven for about 20-25 minutes until tender and slightly crisp on the edges.
While the vegetables roast, bake the chicken in the oven for 18-20 minutes until cooked through and the exterior is crisp.
Remove everything from the oven, let the chicken rest for a few minutes, then slice and serve with the roasted sweet potatoes and broccoli.