Cut the tortillas into 6 triangles each. Add about 1 cup of grapeseed or vegetable oil to a heavy bottom pan over high heat. Once the oil is shimmering, add a few of the tortilla triangles at a time and fry for about 1 minute on each side until they are golden and crisp. Remove from the oil and transfer to a paper towel. Sprinkle with sea salt and repeat for the remaining tortilla wedges.
For the queso:
Heat a small saucepan over medium heat and add butter. Add in the garlic, then stir in the flour to create a roux. Cook for 1 to 2 minutes until the roux is golden, stirring often. Slowly add in the milk while stirring. Stir for a few minutes until it thickens slightly. Add in the grated cheese, one a handful at a time, stirring after each addition until melted.
For the Carne Asada
Place the flank steak in a large baking dish and cover with the marinade for 4-5 hours. Heat a grill over high heat and grill the flank steak for 5 minutes on each side. Remove from the grill and let rest before slicing. Chop for the nachos.
Using 1 regular sized cast iron skillet, layer a handful of the tortilla chips and top them with the carne asada and shredded Monterey jack. Stick the skillet into a 350 degree oven to melt the cheese. Once melted, remove and drizzle with the queso. Then, sprinkle with the pico de gallo, guacamole, cilantro, jalapeños.