Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Drain and rinse the chickpeas, then pat them very dry with a clean kitchen towel; similarly, press the tofu to remove excess moisture and cut into 1/2-inch cubes.
In a large mixing bowl, combine the chickpeas, tofu cubes, broccoli florets, and cauliflower florets.
Drizzle the olive oil over the mixture and sprinkle with sea salt, black pepper, garlic powder, and smoked paprika, tossing thoroughly to coat every piece.
Spread the vegetables, tofu, and chickpeas in a single layer on the prepared baking sheet, ensuring they aren't overcrowded so they roast rather than steam.
Roast for 25 to 30 minutes, tossing the ingredients halfway through the cooking time, until the vegetables are tender-crisp and the tofu and chickpeas are golden brown.
Remove from the oven and immediately sprinkle the nutritional yeast and hemp seeds over the hot mixture.
Finish with a squeeze of fresh lemon juice and serve warm in a large bowl.