Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Slice the chicken breast into thin bite-sized strips and chop the zucchini, cauliflower, and red bell pepper into uniform pieces.
In a large mixing bowl, whisk together the olive oil, cumin, coriander, turmeric, garlic powder, smoked paprika, sea salt, and black pepper.
Add the chicken and vegetables to the bowl and toss thoroughly until every piece is evenly coated in the spice oil.
Spread the mixture in a single layer on the prepared baking sheet, ensuring there is enough space between pieces to allow for roasting rather than steaming.
Roast for 20 to 25 minutes, tossing the ingredients halfway through, until the chicken is cooked through and the vegetables have developed charred, caramelized edges.
While the pan is in the oven, whisk together the Greek yogurt, tahini, and lemon juice in a small ramekin until the sauce is smooth and creamy.
Transfer the roasted chicken and vegetables to a serving bowl and finish by drizzling the lemon-tahini sauce over the top.