Preheat oven to 400°F and line a large baking sheet with parchment paper.
Press the tofu to remove excess moisture, then cut into 1/2-inch cubes.
In a large bowl, toss the tofu, chickpeas, broccoli, and bell peppers with olive oil, garlic powder, smoked paprika, salt, and pepper.
Spread the mixture in a single layer on the baking sheet and roast for 25-30 minutes, tossing halfway through, until the tofu is golden and vegetables are tender.
While roasting, whisk together the tahini, lemon juice, and nutritional yeast in a small bowl, adding a splash of warm water to reach a pourable consistency.
Transfer the roasted vegetables and tofu to a bowl, drizzle with the tahini sauce, and sprinkle with hemp hearts before serving.