In a large saucepan melt butter over medium heat. Add garlic and cook, stirring, about 30 seconds. Add chiles and cook 1 minute more. Stir in flour and salt and cook 1 minute.
Slowly stir in milk and bring to a simmer. Cook, stirring, until thickened, about 5 minutes. Add cream cheese and stir until melted. Take off heat and stir in Cheddar and Monterey Jack until melted.
Serve immediately with Organic Blue Corn Tortilla Chips.