Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
In a large bowl, toss the broccoli florets, bell pepper strips, and zucchini slices with 0.5 tbsp of olive oil and half of the sea salt and black pepper.
Spread the vegetables in a single layer on the prepared baking sheet and roast for 18-20 minutes until tender and slightly charred at the edges.
While the vegetables roast, season the chicken breast on both sides with the dried oregano and the remaining sea salt and black pepper.
Heat the remaining 0.5 tbsp of olive oil in a stainless steel or cast iron skillet over medium-high heat.
Place the chicken in the skillet and sear for 6 minutes without moving it to develop a golden-brown crust.
Flip the chicken, then immediately add the minced garlic and lemon juice to the pan, swirling to coat the chicken as it finishes cooking for another 5-6 minutes.
Ensure the chicken reaches an internal temperature of 165°F, then remove from heat and let rest for 3 minutes before serving with the roasted vegetables.