Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast, zucchini, and red bell pepper into uniform bite-sized pieces, and break the cauliflower into small florets.
In a large mixing bowl, whisk together the olive oil, turmeric, garlic powder, sea salt, and black pepper until well combined.
Add the chicken and all the vegetables to the bowl, tossing thoroughly until every piece is coated in the vibrant golden spice mixture.
Spread the chicken and vegetables in a single, even layer on the prepared baking sheet, ensuring they aren't overcrowded so they roast rather than steam.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the vegetables are tender with slightly charred edges.
Remove from the oven and immediately drizzle with the fresh lemon juice to brighten the earthy turmeric flavors before serving.