Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Slice the zucchini into half-inch thick rounds and toss them in a bowl with 0.5 tablespoons of olive oil, half the sea salt, and half the black pepper.
Spread the zucchini in a single layer on the prepared baking sheet and roast for 18-20 minutes until tender and slightly caramelized.
While the zucchini roasts, season the chicken breast on both sides with the dried oregano, garlic powder, and the remaining sea salt and black pepper.
Heat the remaining 0.5 tablespoons of olive oil in a heavy-bottomed skillet over medium-high heat.
Place the chicken in the skillet and sear for 6 to 8 minutes per side, or until the internal temperature reaches 165°F.
During the last minute of cooking, pour the lemon juice and lemon zest over the chicken, swirling the pan to create a light, aromatic glaze.
Remove the pan from the heat and let the chicken rest for 3 minutes before serving it alongside the roasted zucchini, garnished with chopped fresh parsley.