Preheat your oven to 425°F (220°C). Slice the red and yellow bell peppers into thin strips and cut the red onion into similar-sized slices. Peel and devein the shrimp if not already prepared.
In a large mixing bowl, combine shrimp, sliced peppers, and onions. Drizzle with olive oil, then sprinkle chili powder, cumin, garlic powder, salt, and pepper. Toss to coat evenly.
Spread shrimp and vegetables evenly on a sheet pan in a single layer. Roast for 8-10 minutes, toss with spatula or tongs, then roast another 5-7 minutes until shrimp are opaque and vegetables tender with some char.
While fajitas roast, whisk together sour cream, fresh lime juice, and chopped cilantro in a small bowl to make the chili-lime crema.
Warm the tortillas in the oven or on a dry skillet. Assemble fajitas by spooning shrimp and veggies onto tortillas, drizzle with chili-lime crema, and add optional toppings like avocado, diced tomatoes, or shredded cheese. Serve immediately.
