In a bowl, combine the shrimp, olive oil, chili powder, cumin, garlic powder, salt, and pepper. Toss until the shrimp are evenly coated. Let marinate for 15 minutes.
While the shrimp is marinating, prepare the avocado lime crema. In a blender or food processor, combine the avocado, sour cream, lime juice, and a pinch of salt. Blend until smooth and creamy. Adjust seasoning to taste.
Heat a skillet over medium-high heat. Add the marinated shrimp and cook for about 2-3 minutes on each side, or until they are pink and opaque.
Warm the tortillas in a separate skillet or microwave until pliable.
To assemble the tacos, place a few shrimp on each tortilla, top with shredded cabbage, diced tomatoes, and cilantro. Drizzle with avocado lime crema.
Serve immediately and enjoy!