Prep ingredients: Halve and thinly slice all of the onion lengthwise. Halve poblano pepper, remove stem and seeds, then thinly slice. Finely chop cilantro leaves and stems together.

Season shrimp: Pat shrimp dry. In a medium bowl, toss shrimp with 1 teaspoon oil and 1¼ teaspoons taco seasoning (save rest for step 4).

Toast tortillas: Heat a large skillet over medium-high. Add 1 tortilla at a time to the skillet and toast on one side until warm, about 30 seconds. Transfer to a large sheet of foil, stacking and wrapping to keep warm as you toast remaining tortillas.

Cook onions & peppers: Heat 2 tablespoons of oil in the same skillet over medium-high. Add peppers and cook, stirring, about 2 minutes. Add onions and ½ teaspoon taco seasoning. Cook, stirring frequently, until onions are beginning to brown and peppers are crisp-tender, about 5 minutes.

Add shrimp & corn: Add shrimp, corn, 2 tablespoons water, and half of the chopped cilantro to skillet. Cook, stirring, until shrimp are curled and firm and corn is tender, 3–4 minutes. Remove from heat. Season to taste with salt and pepper.

Make lime crema & serve: In a small bowl, combine all of the sour cream, 1½ teaspoons oil, and 2 teaspoons lime juice. (Add 1 tablespoons water if needed to loosen.) Season to taste with salt and pepper. Cut any remaining lime into wedges. Serve shrimp and veggies in tortillas with lime crema and remaining chopped cilantro over top. Serve with any lime wedges on the side.