Pulse all the sauce ingredients except the sour cream in a food processor. When mostly smooth, add the sour cream and pulse until combined. Taste and adjust as needed. Set aside.
Heat a drizzle of oil a large skillet over medium high heat. Pat the shrimp dry with paper towels and sprinkle with the spices. Add the shrimp to the hot pan and saute for 5-8 minutes, flipping occasionally, until the shrimp are cooked through.
Toss some of the sauce (not all) with the cabbage until it the cabbage is coated to your liking. It should resemble a coleslaw - you want it to be enough sauce so the cabbage is weighed down a little bit. Use leftover sauce on top of the tacos or in other recipes.
To serve tacos, smash a spoonful of avocado on the tortillas, top with a few pieces of shrimp, top with coleslaw, and finish with Cotjia cheese, cilantro, and lime wedges.