Heat a skillet over medium heat. Add chorizo and cook until fully browned and crumbly. Remove from pan and drain excess grease, leaving a small amount for flavor.

Set aside.

In the same pan or a saucepan, melt butter. Add diced onion and cook until soft and translucent. Stir in garlic and cook briefly until fragrant.

This creates a savory base that flavors the entire dip.

Lower heat. Slowly add milk, then gradually stir in cheese in small batches. Stir constantly and avoid high heat to prevent separation.

The mixture should melt into a smooth, creamy sauce.

Once the cheese is fully melted, stir in cooked chorizo and green chilies if using. Simmer gently until thickened and well combined.

Taste and adjust seasoning.