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.
Notes
Of course you can use store-bought chips, no worries. And it also depends on who is coming over and what size skillets you have. Make a large pan for lots of people or smaller pans for couples to share.