Cut through the baguettes to separate all the slices, discarding the end pieces.
Pile the bread slices on top of your biggest baking sheet, all overlapping, as you would with tortillas for nachos. Scatter over most of the cheese, spring onions and crushed tortilla chips as you layer, finishing with a final layer of these toppings. If you’re preparing ahead, you can cover the tray with cling film and chill until ready to cook.
Heat oven to 200C/180C fan/gas 6. Bake for 15 mins until the cheese has melted and the bread is golden and crisp. Loosen the soured cream with enough water to make a more drizzly topping, then spoon over the nachos and sprinkle with some coriander. Serve while everything is still hot and melted.