Preheat the oven to 210C/410F.
Remove the cauliflower stem and separate the cauliflower into individual florets. Slice each floret in 2 or 3 slices and place in a bowl. Drizzle the 2 tbsp of olive oil and the 2 tbsp taco seasoning over the cauliflower slices and toss well. Place on a baking tray over some parchment paper and bake for 20 minutes. Once cooked, remove from the oven.
Dice the tomatoes, red onion and mince the basil and green onion stalk. Combine in a bowl with the salt and pepper. Mix well and set aside.
Dice the yellow pepper. In a frying pan, heat the 1 tsp of olive oil and add the diced pepper. Cook on medium heat for 2 minutes and add the ground beef. Sprinkle in the 1 tsp of taco seasoning, mix well and cook until the meat is cooked through. Set aside.
Peel the avocado, mince the garlic clove and slice the green onion stalk. Combine all of the ingredients for the avocado sauce in a food processor and process until smooth.
On a large serving plate, place the cauliflower and top with the tomato salsa, taco meat and black olives. I added my avocado sauce to a squirting bottle and squirted it over the entire nachos. Serve and enjoy!