Preheat your oven to 400°F (200°C) and heat a grill or grill pan over medium-high heat.
Chop the broccoli, red bell pepper, and zucchini into uniform bite-sized pieces.
Toss the vegetables with 0.5 tbsp of olive oil, 0.125 tsp sea salt, and 0.125 tsp black pepper on a large baking sheet.
Roast the vegetables for 18-20 minutes until they are tender and slightly caramelized.
In a small bowl, whisk the remaining 0.5 tbsp olive oil with the lemon juice, garlic powder, and dried oregano.
Season the chicken breast with the remaining salt and pepper, then brush thoroughly with the lemon-herb marinade.
Grill the chicken for 6-8 minutes per side until the internal temperature reaches 165°F and the outside is golden.
Let the chicken rest for 5 minutes before slicing and serving alongside the roasted vegetables.