Barbecue Pulled Pork Nachos

Name: Barbecue Pulled Pork Nachos
Ingredients: * 1 (2-3 pound) pork shoulder; * 1 large onion, thinly sliced; * 4 teaspoon chili powder; * 1 teaspoon salt; * 3 clove minced garlic; * 1 cup chicken stock; * 4 teaspoon freshly squeezed lime juice; * 1 cup barbecued sauce; green chili cheese sauce:; * 4 tablespoon unsalted butter; * 4 tablespoon all purpose flour; * 2 cup whole milk; * 1 (10 oz ) can chopped green chilie, drained; * 2 cup grated sharp cheddar cheese; * 1/2 teaspoon salt; * 1/4 teaspoon cayenne pepper; garnishment:; * 1 bag white corn tortilla chip; * 2 cup grated monterey jack cheese; * 3/4 cup sour cream; * 1/4 cup green onion, finely sliced; * 1/2 cup sliced pickled jalapeno; * 1 (4 oz ) can sliced black olive