Soak the fresh chickpeas for at least 1 hour, preferably overnight (alternatively you could use canned chickpeas)
Once the chickpeas have been soaked add into a pan then top off with enough water to cover all the chickpeas completely then bring the water to boil before leaving to simmer for 1 hour until cooked through
In the meantime, peel and chop the potatoes into small bite-sized chunks along with preparing the red onions by dicing, slicing the green chillies, and finely chopping the coriander
Once the chickpeas are almost done add the potato chunks into the water then simmer for another 10-12 minutes until the potatoes have softened
Drain the chickpeas and potatoes then set aside to allow to cool completely
Prepare the yoghurt mixture by adding the water into the yoghurt then whisk until well combined
Add the tamarind chutney, salt, chilli powder, cumin powder and chaat masala then mix until combined
Once the chickpeas and potatoes have cooled add all the remaining chaat mixture ingredients into the prepared yoghurt mixture
Transfer the chaat mix into the serving dish then top with the garnish ingredients
Your chana chaat is ready!