Heat the olive oil in a large skillet over medium heat. Add the onion and bell peppers and cook until softened, about 5 minutes. Add the garlic, chili powder, cumin and paprika and cook for 1 minute.
Season with salt and pepper to taste. Add the chicken strips and cook until golden brown and cooked through, about 10 minutes.
Serve with warm tortillas.
Optional: Garnish with chopped fresh cilantro or sour cream.