In a mixing bowl, add yogurt, sour cream, chipotle pepper, minced garlic, lime juice, chopped cilantro, and a pinch of salt. Stir gently until combined.

Using a blender, blend the mixture on medium speed for about 30 seconds until smooth.

Taste the sauce, and add more chipotle if desired, blending for an additional 10 seconds.

If too thick, stir in milk one teaspoon at a time until desired consistency is reached.

Cover and chill in the refrigerator for 30 minutes before serving.