Mix together chili powder, salt, cumin, oregano, garlic powder, and onion powder in a small bowl and set aside.
Heat the olive oil in a medium size skillet over medium high heat for about 2-3 minutes, until the oil is hot. Gently place the chicken breasts in the heated oil and sprinkle about a teaspoon of the taco seasoning onto the top of each chicken breast.
Cook the chicken for about 6 minutes then turn over to cook the other side. Sprinkle the other side of the chicken breast with another teaspoon of the taco seasoning. Allow the chicken to cook for 6 minutes on the other side. Once the chicken is fully cooked, no longer pink on the inside, remove from the skillet and let sit on a plate or cutting board for a couple of minutes before slicing.
Meanwhile prepare the salad by chopping up the green lettuce and layering into a large salad bowl. Top with the diced tomato, shredded cheese, black beans, corn, tortilla chips, avocado, and sliced chicken.
Prepare the cilantro ranch salad dressing by adding all of the ingredients to a blender or food processor and blending until smooth and creamy.
Pour dressing over the salad. Toss to mix. Serve immediately and enjoy!