Preheat oven to 400°F and line a large baking sheet with parchment paper.
Press the extra firm tofu with a heavy object for 15 minutes to remove excess moisture, then cut into 1-inch cubes.
Peel and cube the sweet potato into half-inch pieces and break the broccoli into small florets.
In a large mixing bowl, toss the tofu, sweet potato, chickpeas, and broccoli with olive oil, sea salt, black pepper, and garlic powder until evenly coated.
Spread the mixture in a single layer on the prepared baking sheet and roast for 25 to 30 minutes, flipping halfway through, until the vegetables are tender and the tofu is golden.
While the vegetables roast, whisk together the tahini, lemon juice, and nutritional yeast in a small bowl, adding a teaspoon of warm water at a time until a smooth, pourable consistency is reached.
Assemble the bowl by placing the roasted tofu and vegetable mixture in a serving dish, sprinkling with hemp seeds, and drizzling the creamy tahini dressing over the top.