Having really enjoyed the Mexico City Nachos from Wahaca, I have now been making this dish quite often myself.
I used some tinned black beans, to this I added some tortilla chips, and then dressed the dish with chopped fresh red pepper, avocado, guacamole, sour cream, grated cheese, a homemade tomato salsa, and some homemade pickled red onion.
It was a really nice and fresh dish, and was a good copy of the dish I had in London.