Peel and chop the onion. Rinse the celery, cut into wedges. Scrape the carrots and dice them. Rinse the beans and let them drain well in a colander.
Cook the ground meat in a pan without grease, remove from the pan and drain well on kitchen paper.
Heat olive oil in a pan and fry the onion until transparent. Add the carrots and the celery and mix well. Leave on a low heat for a few minutes.
Add the minced meat, the tomato paste, the tomato cubes and the beans and mix well. Let simmer for 15 minutes on a low heat. Season with pepper and salt.
Preheat the oven grill. Take 4 buttered baking dishes and put in the minced meat.
Sprinkle generously with the tortilla chips and grated cheese and put under the oven grill for a few minutes until the cheese is nicely melted.