Cook bacon until crispy. Set aside.
Heat grill; grill burgers over med-high heat to desired temperature.
While burgers are grilling, prepare queso by combining cheese, milk, and butter in a medium saucepan. Heat over med-low heat, stirring regularly, until cheese is completely melted.
Reduce heat to low; add diced green chiles, cumin, red pepper flakes, and garlic salt.
Add additional milk as needed until queso reaches desired consistency.
Remove burgers from grill.
Assemble burgers by topping each one with cooked bacon, sliced avocado, sliced red onion, sliced jalapeno, and queso.