Coat the chicken breast with taco seasoning. Spray a skillet with cooking spray and heat over medium. Add chicken and cook for 4-5 minutes per side. Check to be sure it is no longer pink and juices run clear.
Dice green pepper, tomatoes, green onions, and shred lettuce. Drain and rinse corn and black beans.
In a very large bowl, combine salad ingredients. Slice chicken and avocado. Add to the salad.