Preheat oven to 400°F and line a large baking sheet with parchment paper.
Dice the tempeh and sweet potato into 1/2-inch cubes and chop broccoli into bite-sized florets.
Rinse and drain the chickpeas, then pat them thoroughly dry with a clean towel.
Place tempeh, chickpeas, sweet potato, and broccoli on the baking sheet.
Drizzle with olive oil and season with garlic powder, sea salt, and black pepper.
Roast for 25-30 minutes, tossing halfway through, until the vegetables are tender and the tempeh is golden brown.
In a small bowl, whisk together the tahini, lemon juice, and a splash of warm water until smooth.
Assemble the bowl by layering the roasted ingredients and topping with nutritional yeast and hemp hearts.
Drizzle the creamy tahini dressing over the top and serve immediately.