Heat grill to medium-high. Scrub grill grates clean, then oil well (see Notes).
Coat chicken evenly with olive oil, then season with salt and pepper.
Place chicken on grill grates and cook for 10-15 minutes, flipping halfway through. Remove from grill when internal temperature reaches 165°F. Total grilling time will vary according to size of chicken breasts and grill temperature. Transfer chicken to a cutting board to cool for 5-10 minutes, then slice into strips.
Salad
Meanwhile, add lettuce to a large serving bowl that's low and wide - or use a large rimmed serving platter. Arrange sliced grilled chicken, corn, tomatoes, cucumber, bacon, queso fresco, red onion, and avocado over the top of the lettuce.
To oil the grates, add some vegetable oil to a small bowl. Then fold a heavy paper towel a few times to make a smaller square. With a tongs, grasp the folded paper towel and dip it into the oil until the paper towel is soaked. Then run the paper towel over the clean, hot grates, repeating until all grill grates are thoroughly oiled.
Nutritional information is calculated without the dressing, as the precise numbers will depend on the amount of dressing used.
Nutrition information is automatically calculated by Spoonacular. I am not a nutritionist and cannot guarantee accuracy. If your health depends on nutrition information, please calculate again with your own favorite calculator.