In medium skillet brown chorizo until no longer pink; drain fat and blot with paper towel. Set cooked chorizo aside.
In medium saucepan melt butter. Add onion and cook 2 minutes.
Whisk in flour; cook 1 minute and whisk in milk. Stir in cheeses until melted.
Stir in chiles, peppers and reserved cooked chorizo. Transfer cheese dip to serving dish. Serve with Mission Thin & Crispy Tortilla Chips.