Quick Chicken Fajitas

Name: Quick Chicken Fajitas
Ingredients: 8 (6-in.) corn tortillas; 1 ½ teaspoons chili powder; 1 teaspoon ground cumin; ½ teaspoon salt, divided; ¼ teaspoon black pepper; 1 pound skinless, boneless chicken breasts, cut crosswise into 1/4-in.-thick slices; 1 tablespoon olive oil; 1 ½ cups thinly sliced red and orange bell pepper (about 1 small of each); 1 ½ cups thinly sliced red onion; 1 ½ ripe peeled avocados; 2 teaspoons fresh lime juice; ¼ cup light sour cream (optional); 3 tablespoons cilantro leaves (optional); 4 lime wedges