Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Place the broccoli florets, diced bell pepper, and sweet potato on the sheet; toss with 0.5 tbsp olive oil and half the salt and pepper.
Roast the vegetables for 20 to 25 minutes, tossing halfway through, until the sweet potatoes are tender and the broccoli is crisp-edged.
While vegetables roast, season the chicken breast evenly on both sides with the dried oregano and the remaining salt and pepper.
Heat the remaining 0.5 tbsp olive oil in a medium skillet over medium-high heat.
Place the chicken in the skillet and sear for 5 to 7 minutes per side, or until the internal temperature reaches 165°F.
Reduce heat to low, add the ghee, minced garlic, and lemon juice to the pan, and spoon the bubbling sauce over the chicken for 1 minute.
Transfer the chicken to a plate alongside the roasted vegetables and drizzle any remaining lemon-garlic pan juices over the top.