Open chorizo and put in a non-stick skillet over medium heat.
Add minced jalapeno and onion to chorizo. Cook until chorizo is done and onion and jalapeno are softened up.
When chorizo is done cooking, make sure the cooked chorizo/onion mixture has at least 4 tablespoons of fat (eyeball it) add butter to make up the difference
Add in flour, and cook two minutes, stirring constantly.
Slowly add in milk a little at a time, stirring constantly.
Turn down the heat a little, and stir in the cheese.
When cheese has melted, stir in the fresh chopped tomato.
Add in a dash of garlic powder (optional).
Taste for salt.
Serve with tortilla chips.