Preheat oven to 425F with a rimmed baking sheet inside.
Combine chili powder, cumin, smoked paprika, garlic powder, salt, and pepper.
Toss bell peppers and onion with 2 tablespoons olive oil and half the spice blend.
Spread vegetables on the hot sheet pan and roast for 12 minutes.
Toss shrimp with remaining oil and spice blend.
Remove pan, add shrimp among the vegetables, and roast 7-8 minutes until shrimp is pink and opaque.
Squeeze lime juice over everything, scatter with cilantro, and serve with warm tortillas.