In a mixing bowl, combine olive oil, chili powder, cumin, garlic powder, and salt; toss with shrimp to coat evenly.
Preheat a grill or grill pan to medium-high heat (approximately 400°F/200°C).
Thread shrimp onto skewers or place directly on the oiled grill grates.
Grill shrimp for 2 to 3 minutes per side until pink, opaque, and slightly charred.
Warm corn tortillas on the grill for 30 seconds per side until pliable.
In a small bowl, whisk together Mexican crema and lime juice.
Assemble tacos by layering cabbage, 3-4 grilled shrimp, cilantro, and a drizzle of lime crema on each tortilla.
Serve immediately with lime wedges on the side.