Preheat the grill to medium-high heat.

Rub the flank steak with 1 tablespoon of Emeril's Southwest Seasoning and set aside at room temperature for 1 hour.

In a medium-size saucepan, heat the olive oil over medium heat. Once hot, add the onion and bell pepper and cook, stirring occasionally, for 4 to 5 minutes. Add the jalapeno, garlic, black beans, the remaining Southwest Seasoning and 1 teaspoon of the salt. Continue to cook for 10 to 12 minutes or until the liquid has mostly evaporated. Remove from the heat but keep warm.

Season the steak with the remaining 1 teaspoon of salt. Transfer the flank steak to the grill and cook for 4 minutes per side. Transfer the steak to a platter and let it rest for 5 to 7 minutes. Slice the steak into very thin 2-inch long strips and then into bite size pieces.
 

Preheat the oven to broil.

To assemble the nachos, arrange a layer of chips on a heat-proof platter, sprinkle about 1/3 of each cheese over the chips, spoon 1/3 of the beans over the cheese and 1/3 of the beef over the beans. Repeat this process two more times. Broil the nachos for 2 to 3 minutes just to melt the cheese. Remove from the oven and add the shredded lettuce, tomatoes, avocado and sour cream. Garnish with the cilantro sprigs.

Serve immediately.