Cut the mini tortillas into triangles (I cut each into 8), and lay them out on a baking tray. Keep them in a single layer if you can, but it's okay if they overlap a bit. Spray them lightly with oil, and add a pinch of salt and pepper. Place under a medium grill (broiler) for a couple of minutes, until golden brown. Then, flip each tortilla chip over and repeat with the other side.
When the tortilla chips are ready, layer them up (on a baking tray covered in baking paper) with the cheese, tomato, black beans and hot sauce - I ended up with three layers of each. Place back under the grill (don't have the temperature up too high - you want to try to melt the cheese all the way through, rather than just brown the top).
While the nachos are grilling, fry your eggs to your preference - I did mine sunny side up. Also dice your avocado.
When the nachos are hot and crispy, top them with the fried eggs and diced avocado. Serve immediately.