Preheat the oven to 400°F (200°C) and lightly grease a baking sheet with olive oil.

In a large mixing bowl, combine the shredded chicken, black beans, diced tomatoes, ground cumin, chili powder, salt, and pepper. Stir thoroughly.

Warm the corn tortillas in a skillet over medium heat for about 30 seconds on each side until pliable.

Fill each warmed tortilla with a generous scoop of the chicken mixture and a sprinkle of shredded cheddar cheese. Fold in half and place seam-side down on the prepared baking sheet.

Brush the tops of the tacos with more olive oil and bake for 20–25 minutes until crispy and cheese is melted.

While baking, combine avocado, sour cream, lime juice, cilantro, salt, and pepper in a blender and blend until smooth.

Drizzle avocado sauce over the baked tacos and serve warm with optional toppings.