In a blender, combine half a ripe avocado, sour cream, fresh lime juice, and a pinch of kosher salt. Blend until smooth and creamy, adding a splash of water to reach desired consistency. Transfer to a bowl and refrigerate while preparing the tacos.

Heat a non-stick skillet over medium heat and add a tablespoon of oil. Once hot, add the ground turkey and chopped onion, stirring occasionally until browned, about 4-5 minutes.

Lower heat and stir in drained black beans and green chiles. Sprinkle in spices and add a splash of water. Let simmer for 15 minutes, stirring occasionally.

Preheat oven to 400°F (200°C). Arrange tortillas on a baking sheet, sprinkle cheese, and spoon turkey filling down the center. Bake for 10-12 minutes until edges are golden.

Remove from oven, let cool slightly, and serve with creamy avocado sauce for dipping.