Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Place the cubed sweet potatoes, broccoli florets, and sliced red bell peppers on the baking sheet.
Drizzle the vegetables with half of the olive oil and sprinkle with a pinch of the sea salt and black pepper, tossing to coat evenly.
Roast the vegetables in the oven for 20-25 minutes until they are tender and slightly browned at the edges.
While the vegetables roast, season the chicken breast on both sides with the dried thyme, dried rosemary, and the remaining salt and pepper.
Heat the remaining olive oil in a medium skillet over medium-high heat.
Add the chicken breast to the skillet and sear for 5-7 minutes per side, or until the internal temperature reaches 165°F.
In the final minute of cooking, add the minced garlic and lemon juice to the pan, swirling to combine and spooning the pan sauce over the chicken.
Remove from heat and serve the lemon-herb chicken alongside the roasted vegetable medley.