How to Make It
Working with 1 tortilla at a time, heat tortillas over medium-high heat in a large, dry skillet for about 20 seconds on each side or until lightly charred. Wrap tortillas in foil; keep warm.
Combine chili powder, cumin, 1/4 teaspoon salt, and black pepper in a bowl. Add chicken; toss to coat. Heat pan over medium-high heat. Add oil; swirl. Add chicken; cook 3 minutes. Add bell peppers and onion; cook 5 minutes or until vegetables are softened and chicken is done, stirring occasionally.
Place avocados in a bowl; coarsely mash with a fork. Add remaining 1/4 teaspoon salt and lime juice, stirring to combine. Divide chicken mixture among tortillas; top evenly with avocado mixture. Top evenly with sour cream and cilantro, if desired. Serve with lime wedges.