In a medium saucepan over low heat, put the shredded cheddar cheese and milk together.
Stir the cheese and milk until the cheese is all melted, and the mixture becomes smooth.
Add the diced green chilies, chopped jalapeño peppers, cumin, garlic powder, and salt to the melted cheese mixture.
Stir everything together until it's all mixed and heated through.
Taste the queso and see if you like the flavors. You can add more salt, cumin, or spice if needed.
Serve your delicious Tijuana Flats queso immediately with tortilla chips.
You can also use it as a yummy topping for nachos, tacos, or burritos.