Heat your oven to 180°C/Fan 160°C/Gas 4. Chop two of the tortillas into little triangles. Spread them out on a baking tray. Bake for 8-10 mins till they’re golden brown and crisp.
Peel and finely slice the red onion. Finely zest and juice the lime. Put the lime juice in a bowl. Measure out 1 tbsp of the caster sugar and stir it into the lime juice with a pinch of salt. Stir in the red onion. Put to one side.
Drain the sweetcorn. Warm a dry frying pan over a medium heat. Add the sweetcorn kernels. Fry, stirring now and then, till the corn is toasted, golden and starting to pop.
Tip the toasted sweetcorn into a bowl. Finely slice the chilli. Add it to the sweetcorn with the lime zest and a pinch of salt and pepper. Stir to mix.
Separate the lettuce leaves and shred them. Dice the cucumber and the tomatoes. Tumble the salad into a bowl. Add 2 tsp oil and some salt and pepper. Toss to mix.
Slice the chicken breast mini fillets into long thin fingers. Warm 2 tsp oil in the frying pan. Add the chicken. Cook and stir for 8-10 mins till the chicken is golden and cooked through.
Scatter the nachos over two plates or shallow bowls. Layer up with the salad and toasted sweetcorn. Top with the chicken. Heap on the red onions. Drizzle over the lime juices. Garnish with coriander leaves to serve.