Heat the butter in a large frying pan on a medium heat until just bubbling, then add the mushrooms to the pan in a single layer. Turn the heat up to medium-high and fry for 6-8 minutes, turning once or twice until they start to turn golden (you may need to do in two batches if your pan isn't big enough to fit them in a single layer). Add the salt, pepper, garlic and chillies and cook, whilst moving around the pan for a further two minutes. Turn off the heat.
Layer the nachos on a large serving plate and top with garlic-chilli-mushrooms.
Crumble up the Lancashire cheese and sprinkle on top along with the fresh coriander. Serve straight away.
If you prefer the nachos to be hot, place in the oven at 200c/400f (before sprinkling on the coriander) for 2 minutes. Take out of the oven and sprinkle on the coriander..Nutritional Information is per serving.