Heat oil inside a large pan over medium-high heat. Season chicken breasts with taco seasoning and cook the first side for 6 minutes and flip, cooking the other side for another 5 minutes, until the internal temperature has reached 165F. Remove from pan and set aside.
In a large bowl or serving platter, place chopped lettuce. Top with black beans and corn.
Chop chicken breasts and distribute over salad. Top with cherry tomatoes, shredded cheese, and avocado.