Preheat oven to 180-c and place rack on medium level
In a large pan sauté Onions, and sauté for 2-3 minutes until soft, add Minced Beef, Garlic, Chili Powder, Cumin, Oregano, and Black pepper and cook until beef is fully cooked. Remove from heat and set aside
Meanwhile prepare sauce by combing skimmed milk and MAGGI Béchamel Mix, stir over medium high heat until slightly thick; add Mashed Beans and stir until smooth
Pour half the Béchamel sauce into a ovenproof baking dish, spoon the cooked beef on top and sprinkle half of the cheese over beef; pour the remaining sauce over the beef and top with the remaining cheese
Bake in preheated oven for 20 minutes until cheese is melted and slightly golden. Remove from oven; crush Tortilla chips over the cheese
Layer Lettuce, Tomato, Avocado, Black Olives and Jalapeno over the chips right before serving