Shrimp Tacos with Cilantro-Lime Crema

Cilantro-Lime Crema Sauce
1/4 cup sour cream*
1/4 cup mayonnaise
1 1/2 Tbsp fresh lime juice
3 Tbsp very finely chopped cilantro
1 clove finely minced garlic
Salt and freshly ground black pepper
Shrimp
1 lb medium shrimp**, peeled, deveined and tails removed
1/2 tsp chipotle chili powder***
1/2 tsp chili powder
1/2 tsp ground cumin
1/4 tsp ground paprika
1/4 tsp ground coriander
1/2 tsp salt, or to taste
1/4 tsp freshly ground black pepper
1 Tbsp olive oil
For Serving