Preheat oven to 400°F and line a large baking sheet with parchment paper.
Press the tofu to remove excess moisture, then cut into 1-inch cubes.
In a bowl, toss tofu with nutritional yeast, garlic powder, onion powder, salt, and pepper until evenly coated.
Place tofu, broccoli, cauliflower, and chickpeas on the baking sheet, drizzle with olive oil, and toss gently.
Roast for 25-30 minutes, flipping halfway through, until the tofu is golden and vegetables are tender.
While roasting, whisk together tahini, lemon juice, and tamari in a small bowl, adding a splash of water to reach a pourable consistency.
Assemble the bowl by placing cooked quinoa at the base and topping with the roasted tofu and vegetable mixture.
Drizzle the creamy tahini dressing over the top and serve warm.