Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Chop the red bell pepper and zucchini into bite-sized pieces, ensuring they are uniform for even roasting.
In a large mixing bowl, toss the broccoli florets, chopped bell pepper, and zucchini with 0.5 tbsp of olive oil, 0.25 tsp sea salt, and 0.25 tsp garlic powder.
Spread the vegetables in a single layer on the prepared baking sheet and roast for 18-20 minutes until they are tender and slightly caramelized at the edges.
While the vegetables are roasting, pat the chicken breast dry with a paper towel and season both sides with the remaining sea salt, black pepper, garlic powder, and dried oregano.
Heat the remaining 0.5 tbsp of olive oil in a medium skillet over medium-high heat until shimmering.
Add the chicken breast to the pan and sear for 6-7 minutes per side, or until the internal temperature reaches 165°F and the outside is golden brown.
Remove the chicken from the pan and let it rest for 3-5 minutes before slicing it against the grain.
Plate the sliced chicken alongside the roasted vegetables and serve immediately.