Preheat oven to 210 °C or 200 °C fan bake. Line an oven tray with baking paper.
Prep potatoes
Wash then slice 800 g potatoes with a mandolin if you have one, otherwise carefully slice into 2mm thick rings (keep them an even thickness so they cook at the same time).
Cook potatoes
Spread the sliced potatoes out in a single layer on the prepared oven tray and spray with oil spray. Season with salt and pepper. Bake for 15 minutes, then flip and return to oven for a further 15 minutes or until crispy and cooked through.
Cook beef
Peel and mince 2 cloves garlic. Peel and dice 1 brown onion. Heat 1 tbsp olive oil in a large frypan on medium-high heat. Add the garlic and onions and cook for 1 minute. Add 500 g beef mince and cook for 4 minutes, until lightly browned. Add 400 g diced tomatoes, ⅓ cup vegetable stock and 2 tbsp Mexican seasoning and cook a further 5-8 minutes or until thickened.
Toppings
Shred the leaves of ½ lettuce. Slice 1 avocado into wedges. Slice 250 g cherry tomatoes in half. Peel and finely dice 1 red onion. Grate 50 g cheese. Slice 1 lime into wedges. Roughly chop 1 bunch coriander.
To finish
You can assemble these onto individual plates, one large serving dish or even leave them on the baking tray (be careful, it will be hot). Assemble the potato nachos around the sides, then add shredded lettuce, beef mixture, avocado, cherry tomatoes,red onion and cheese.
To serve
Serve the loaded beef tacos and potato nacho chips with lime wedges on the side for squeezing. Garnish with coriander and sour cream.