Preheat the oven to 475 degrees F or preheat the broiler, with the rack positioned about 7 inches from the top of the oven or the heat source.
Assemble the nachos: Arrange the chips on a 12 by 18-inch baking sheet or ovenproof platter. Top each chip with a layer of Monterey Jack, followed in order by the chiles, sirloin, and cheese blend.
Bake the nachos for 5 to 7 minutes, or broil, until the cheese is soft and bubbly.
Before serving, squeeze streaks of Avocado Crema and Chipotle Mayonnaise, to taste, over the nachos, if using, and garnish with lettuce and onions.
In a small bowl, combine the salt, chile, cumin, garlic, cinnamon, and pepper. Rub the steak all over with the mix. Set aside at room temperature for 15 minutes.
Heat a grill or the broiler until very hot. Rub the steak all over with the olive oil and soy sauce. Grill or broil the steak very close to the heat, about 3 minutes per side, until medium rare. Set aside for 10 minutes before slicing or dicing.
Puree all the ingredients in a food processor or blender. Funnel into a squeeze bottle. The mixture should be thin enough to streak easily. If not, add a few drips more lime juice or buttermilk. Plug the top of the nozzle with a toothpick and chill until read to use. The mixture will keep for 2 days refrigerated.
Recipe courtesy of Kate Heyhoe, Macho Nachos, Clarkson Potter, 2003