Put the pancetta into a large pan and put in a medium heat. Cook for 3-4 minutes until golden.
Peel and chop the onion and garlic. Add to the pan and cook for another minute. Add the beef mince and cook for five minutes until browned.
Add the cinnamon and smoked paprika. Stir, then add the passata and 400 ml water. Turn the heat down to low and simmer for 60-90 minutes until thickened. Dice the red pepper and finely chop the coriander. Add to the chilli and turn off the heat.
Meanwhile, peel the potatoes and chop into 1-2 inch chunks. Put in a saucepan and cover with cold water. Bring to the boil and cook for 25-30 minutes until very soft.
Drain the potatoes and return to the pan. Add the soured cream and a pinch of salt and pepper. Mash until smooth.
Preheat the oven to 180 degrees C.
Put the chilli at the bottom of a large ovenproof dish. Top with the mashed potato and smooth it down until even. Crush the tortilla chips into small chunks and sprinkle evenly over the top, then add the cheese. Put in the oven for 30 minutes until golden and bubbling.