Begin by preparing the avocado lime sauce. In a blender or food processor, combine the avocado, Greek yogurt, lime juice, minced garlic, and a pinch of salt and pepper. Blend until smooth and creamy. Set aside.

In a medium bowl, mix together the olive oil, chili powder, cumin, garlic powder, onion powder, paprika, salt, and black pepper to create a marinade.

Cut the chicken breasts into bite-sized pieces and add them to the marinade, ensuring they are well coated. Let the chicken marinate for at least 15 minutes for maximum flavor.

Heat a large skillet over medium-high heat. Add the marinated chicken and cook for about 6-8 minutes, or until the chicken is cooked through and no longer pink in the center. Stir occasionally to ensure even cooking.

While the chicken is cooking, warm the tortillas in a separate skillet or microwave until soft and pliable.

To assemble the tacos, place a generous portion of the cooked chicken on each tortilla. Top with shredded lettuce, diced tomatoes, and shredded cheddar cheese.

Drizzle the avocado lime sauce over the top of each taco and serve immediately.