Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Dice the sweet potato into small cubes and chop the broccoli and bell pepper into uniform bite-sized pieces to ensure even roasting.
Place the vegetables on the pan, drizzle with half of the olive oil, and sprinkle with a portion of the sea salt and black pepper.
Roast the vegetables for 20 to 25 minutes, tossing halfway through, until the sweet potatoes are golden and the broccoli is crisp-tender.
Season the chicken breast on both sides with the dried rosemary, thyme, and the remaining salt and pepper.
Heat the remaining olive oil in a skillet over medium-high heat and sear the chicken for approximately 6 minutes per side until the internal temperature reaches 165°F.
Add the minced garlic to the pan during the final minute of cooking, then deglaze the pan by squeezing the fresh lemon juice over the chicken.
Rest the chicken for 3 minutes before slicing and serving alongside the vibrant roasted vegetable medley.