Preheat the oven to 425°F (220°C).
In a large bowl, combine the shrimp, olive oil, chili powder, ground cumin, smoked paprika, garlic powder, onion powder, salt, and black pepper. Toss until the shrimp are evenly coated.
Arrange the seasoned shrimp in a single layer on a large sheet pan.
Place the sheet pan in the oven and bake for 10 to 12 minutes, or until the shrimp are pink and cooked through.
While the shrimp are baking, prepare the cabbage slaw by combining shredded green cabbage, chopped cilantro, diced red onion, fresh lime juice, and salt in a medium bowl. Toss well and set aside.
To make the avocado sauce, place the sour cream, avocado, lime juice, salt, and water in a blender or food processor. Blend until smooth and creamy. Add more water if needed to reach desired consistency.
Warm the corn tortillas in a dry skillet over medium heat for about 30 seconds on each side or until pliable.
To assemble the tacos, place a few shrimp on each tortilla, top with a generous amount of cabbage slaw, and drizzle with the avocado sauce.
Serve immediately with extra lime wedges if desired.