Coat ribs thoroughly with taco seasoning rub. Rub them really well and let them sit for a few minutes.
Line a baking sheet with aluminum foil and back ribs, meat side down, at 250 degrees for 4 hours.
Every hour, flip the ribs and baste them well with apple cider vinegar.
Remove ribs when done and chop them up. Use a knife to slice off meat and chop all meat finely.
To make cheese sauce, add butter and flour to a medium pot over medium heat. Whisk until butter is melted and the roux starts to cook. After a few minutes it should turn a light brown color and be very thick.
Start slowly whisking in milk. Work slowly so the sauce doesn’t get clumpy. You will need 2-3 cups of milk.
Once milk is stirred in, stir in green chiles and grated cheese. Turn heat down to low and keep warm until needed. If it gets too thick, stir in a bit more milk.
On two baking sheet, add a thick layer of tortilla chips. Top with shredded rib meat, red onions, and salsa. Bake at 350 degrees for 8-10 minutes.
Remove and scoop nachos onto plates. Drizzle cheese sauce over plates and top with shredded cheese, jalapenos, avocado, and any other toppings you want. Serve immediately!