Preheat the oven to 180°C.
Heat the oil in a large frying pan over high heat and brown the mince for 5 minutes or so, breaking up any large lumps as you go.
Add the spices, onion and garlic and cook for another 5 minutes until the onion has softened.
Add the tomato paste, black beans and tinned tomatoes. Half-fill the tomato tin with water and swish it around, then add to the pan. Season with the salt.
Simmer over medium heat for 10 minutes so it reduces a bit.
Meanwhile, for the cheese sauce, make the béchamel, adding the milk slowly until the sauce is smooth. Fold in the grated cheese until melted and combined. Mmmm.
Transfer the mince mixture to an ovenproof dish and nestle the corn chips on top.
Drop spoonfuls of cheese sauce over the meat and corn chips.
Bake for 10 minutes until golden and bubbly.
While that’s happening, make the guacamole by combining all the ingredients in a bowl.
Ditto for the tomato salsa.
Eat the nachos with the guacamole, tomato salsa and sour cream.