For the chicken: Generously sprinkle both sides of the breasts with the taco seasoning. Heat the oil and butter in a large skillet over medium-high heat. Cook the chicken on both sides until deep golden brown on the outside and done in the middle (or to an internal temperature of 165 degrees F), about 4 minutes per side. Set aside to cool for 5 minutes.
For the dressing: While the chicken is cooking, pour the ranch dressing into a bowl. Add the salsa and cilantro and stir to combine.
For the salad: Next, place the ears of corn in the skillet you used to cook the chicken and roll them around so that the flavorful oil/butter mixture coats the corn. Grill on a grill pan or cook in a separate skillet until the corn is still crisp but has color on the outside. Slice off the kernels with a sharp knife and set aside. Dice the chicken into cubes.
On a platter, layer the shredded lettuce, diced chicken, tomatoes, cheese, corn, avocados, green onions, cilantro and crushed chips. Drizzle the dressing all over the top, saving some to serve on the side if you'd like. Serve the salad in individual bowls.