Barbecue Pulled Pork Nachos

Name: Barbecue Pulled Pork Nachos
Ingredients: 3 pounds Pork Shoulder; 1 whole Onion, Thinly Sliced; 4 teaspoons Chili Powder; 1 teaspoon Salt; 3 cloves Garlic, Minced; 1 cup Chicken Stock; 4 teaspoons Freshly Squeezed Lime Juice; 1 cup Barbecue Sauce; 4 Tablespoons Unsalted Butter; 4 Tablespoons All-purpose Flour; 2 cups Whole Milk; 10 ounces, weight Can Chopped Green Chilies, Drained; 2 cups Grated Sharp Cheddar Cheese; ½ teaspoons Salt; ¼ teaspoons Cayenne Pepper; 1 bag White Corn Tortilla Chips, 13 Ounce Bag; 2 cups Grated Monterey Jack Cheese; ¾ cups Sour Cream; ¼ cups Sliced Green Onions; ½ cups Pickled Jalapeños; 4 ounces, weight Sliced Black Olives