Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Slice the green cabbage into 1-inch thick wedges, keeping the core intact so they stay together during roasting.
Arrange the cabbage wedges, chicken breast, and rinsed chickpeas in a single layer on the prepared baking sheet.
Drizzle 0.5 tbsp of olive oil over the ingredients and season with half of the sea salt, black pepper, and garlic powder.
Roast for 20 to 25 minutes, or until the chicken is cooked through and the cabbage edges are golden and caramelized.
While the tray roasts, whisk together the remaining olive oil, lemon juice, dried oregano, and chopped parsley in a small bowl.
Slice the roasted chicken into thin strips and plate alongside the tender cabbage and chickpeas.
Spoon the zesty lemon-herb dressing over the entire dish before serving warm.