When using a blender with a “soup” option:

Simply blend all ingredients on soup mode and use immediately.

If you don’t have a “soup” option:

Blend all ingredients in a blender or food processor until everything is smooth and creamy.

To warm your nacho cheese sauce, simply pour your into a small saucepan over medium low heat.

Stir constantly until your sauce has reached your desired temperature. 

Serve immediately.