For the Steak; Prepare the marinade linked above, and marinate your steak or chicken for at least 8 hours, preferably overnight. Remove from the marinade and cook thoroughly on the grill or in an oiled hot cast iron pan. Reserve.
For the Poblano Crema; On the hot grill, quickly char your poblano pepper. Place over the flames and rotate every 30 seconds until the pepper skin starts to blister & color. Allow to cool. Next with a paper towel, gently rub off the skin as best as you can. Using a sharp knife, cut the sides of the pepper away from the seeds. In a blender; add the seeded charred pepper, sour cream, garlic clove, cilantro, lime juice, salt and onion powder. Blend on high until smooth. Pour into a squeeze bottle or bowl, cover and chill until needed.
For the Black Beans; Rinse the canned beans well under cold running water. Place in a small saucepan with two cloves of peeled fresh garlic, 1 cup (or enough broth to just cover the beans) beef stock, onion powder, and salt & pepper. Place over medium-high heat and let come to a boil. Turn the heat down to a simmer, and while mixing occasionally, boil off the broth until the beans become creamy & the garlic has softened. About 30 minutes. If the beans need more time, add a splash more of the beef broth and continue simmering. Adjust salt & pepper to taste. Reserve.
For the Fresh Salsa; Add the chopped tomatoes, red onion, diced jalapeno, chopped cilantro, lime juice, olive oil and seasonings to a medium sized bowl. Stir well. Reserve.
To Assemble the Nachos; Preheat your oven to 350F, and line a large baking sheet with parchment paper. Spread out the bagged tortilla chips, making sure not to use the broken pieces. Next, spread the shredded cheese evenly across the chips. Now, add generous spoonfuls of the seasoned black beans. Pop into the oven for 5 minutes, or just until the cheese has started to melt. After 5 minutes, remove from the oven to a cooling rack and begin to layer on the sliced steak (or chicken breast) & fresh salsa. Place back into the hot oven for 5-7 minutes.
To Finish; Remove the nachos from the oven and place on a cooling rack. Add slices of fresh avocado & cilantro. Add dollops of sour cream and sliced jalapenos. Using a squirt bottle or large spoon, generously drizzle on your poblano crema over the nachos.