Spray a large frying pan or wok with low-calorie cooking spray and place on a medium to high heat.
Add the onions, peppers and carrots. Sauté for 5 minutes until soft.
Add the garlic, cumin, oregano and smoked paprika and cook for another minute, until fragrant.
Stir in the chipotle paste and tomato puree. Add the chopped tomatoes, stock, Henderson's relish and courgettes. Bring to the boil, then reduce the heat to low to medium and allow to simmer for 20 minutes, stirring occasionally.
Meanwhile, place the potatoes in a pan of cold, salted water, bring to the boil, reduce heat and cook for around 15-20 minutes until a knife easily slides through the potatoes. Drain and mash well. Stir in two thirds of the cheese. Taste and season with salt and pepper, if you wish. Preheat the oven to 200°C.
After the veg has been cooking for 20 minutes, stir in the beans. At this point, check your sauce and increase the heat if you think it is too thin. Cook for another 5 minutes until the vegetables are cooked and the sauce has thickened. Taste and season with salt and pepper, if you wish.
Pour the filling into an ovenproof dish, and top with the cheesy mash.
Sprinkle the lightly-crushed tortilla chips over the potato ,and then top with the reserved grated cheese.
Place in the oven for 20 minutes, until the top is golden and crisp.
Serve with steamed vegetables or salad!