In a large mixing bowl, combine the shredded chicken, black beans, corn, bell peppers, and red onion. Mix well to combine all the ingredients evenly.
In a separate bowl, whisk together the Greek yogurt, mayonnaise, lime juice, chili powder, cumin, salt, and pepper until smooth.
Pour the dressing over the chicken mixture and stir until everything is well coated.
Lay out the whole wheat tortillas on a flat surface. Divide the chicken mixture evenly among the tortillas, placing it in the center of each.
Top each wrap with shredded lettuce and avocado slices. If desired, add a spoonful of salsa on top.
Fold in the sides of the tortillas and then roll them up tightly from the bottom to the top.
Slice each wrap in half and serve immediately, or wrap in foil and refrigerate for up to 2 hours before serving.