Chicken Nachos with Green Chili-Cheese Sauce

Ingredients

• tomatillos

  husked and rinsed (or used canned if unavailable)
  4 medium
• jalapeños

  stemmed
  2 unit
• onion

  peeled and quartered
  ½ medium
• garlic cloves

  peeled
  2 unit
• handful fresh cilantro leaves

  coarsely chopped
  1 unit
• lime

  juiced
  1 unit
• toasted cumin seeds
  1 teaspoon
• kosher (coarse or margarita) salt
  1 unit
• [60ml] (½ stick) unsalted butter
  ¼ cup
• all-purpose [60ml] flour
  ¼ cup
• (480ml) chicken stock

  at room temperature
  2 cups
• (950ml) shredded jack cheese
  4 cups
• (1-pound) (450g) bag salted corn tortilla chips
  1 unit
• (3-pound) whole (1350g) roasted chicken

  meat finely shredded, skin and bones discarded
  1 unit