Prepare spicy sauce by shaking together sour cream and sriracha in a squeeze bottle.Rinse and dry frozen shrimp.Cook shrimp in butter over medium heat. Stir frequently and cook just until shrimp has all turned pink.
Briefly place soft taco shells on skillet to soften and warm both sides. Arrange two of three shells on a plate. Fill with a layer of cabbage. Top with shrimp.