Preheat oven to 180°C (350°F) and line a baking tray.
Combine turmeric, cumin seeds, nigella seeds, and lemon zest. Mix in lemon juice, garlic, and olive oil to form a golden paste.
In a large bowl, combine potatoes, chicken, onion, pepper, and coriander. Pour in spice mix and coat evenly. Season with salt and pepper.
Spread evenly on a baking tray and roast for 50 minutes, stirring halfway through.
Remove from oven, scatter fresh coriander, and serve hot with green vegetables or chutney.
