Heat butter in a saucepan.
Add flour and whisk until smooth.
Slowly pour milk while stirring constantly.
Let it thicken on medium heat.
Add heavy cream and stir well.
Mix in garlic and onion powder.
Add chili powder and paprika.
Stir until spices blend evenly.
Add green chilies for flavor.
Slowly add shredded cheddar cheese.
Stir until cheese melts completely.
Add Monterey Jack cheese next.
Mix until queso is creamy smooth.
Season with salt and pepper.
Serve warm with tortilla chips.