Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Chop the broccoli, red bell pepper, and zucchini into uniform, bite-sized pieces.
Place the chicken breast and chopped vegetables onto the prepared baking sheet.
Drizzle everything with olive oil and season evenly with sea salt, black pepper, and dried oregano.
Toss the chicken and vegetables to ensure they are well-coated, then spread them out in a single layer.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender.
While the meal roasts, whisk together the tahini, lemon juice, and water in a small bowl until the sauce is smooth and pourable.
Once cooked, slice the chicken into strips and serve alongside the roasted vegetables, drizzling the creamy tahini sauce over the entire plate.