Step 1

Heat oil in a large wok or cast-iron or other stick-resistant skillet (not Teflon-based nonstick, see Tip) over high heat. Add chicken, vegetables, chili powder, and salt; cook, tossing with tongs occasionally, until the chicken is cooked through and the vegetables begin to brown, about 7 minutes.

Step 2

Meanwhile, stack tortillas and wrap in a barely damp, clean kitchen towel (or paper towel). Microwave on High for 30 to 45 seconds.

Step 3

Divide the chicken-and-vegetable mixture among the tortillas. Top each with 2 Tbsp. guacamole and 2 Tbsp. yogurt. Serve with lime wedges and garnish with cilantro if desired.