To make the chicken: Cut the chicken breasts into 1-inch cubes. Season with the salt and pepper.
In a large skillet, heat the olive oil over medium-high heat. Add the chicken and cook, turning occasionally, until cooked through, about 7-8 minutes. Add the hot sauce and use a spatula to stir, making sure the chicken is evenly coated. Set aside.
Meanwhile, make the Buffalo ranch dressing: In a small bowl, whisk together the ranch dressing and hot sauce. Refrigerate until ready to serve.
To assemble the salad: In a large shallow bowl or on a large platter, combine the romaine lettuce and the iceberg lettuce. Layer the chicken pieces, eggs, carrots, celery, red onion, cheese, avocado, bacon, and grape tomatoes in neat rows over the lettuce.