Make the Dressing: In a small bowl, whisk to combine the mayonnaise, yogurt, garlic, powder, onion powder, parsley, chives, salt, and pepper. Mix well.
Whisk in the vinegar, followed by 3/4 cup buttermilk. Slowly add more buttermilk if you desire a thinner consistency. Set ¾ cup of the dressing aside for the salad and cover and store the rest in the refrigerator for other uses. It will keep for up to 5 days.
Make the chicken salad: In a small bowl, combine all blackened seasoning ingredients. Season the chicken cutlets on both sides with the mixture.
In a large skillet, heat 2 teaspoons olive oil over medium-high heat. Add half of the chicken cutlets and allow to cook for 5 minutes per side. Remove to a plate. Turn the heat down slightly and add the remaining 2 teaspoons of olive oil. Add the remaining chicken cutlets and cook for 5 minutes per side. Remove to the plate with the rest of the cooked cutlets. Cover and set aside while you prepare the salads.
To serve: Divide the mixed salad among four large bowls or plates, and drizzle each salad with about 3 tablespoons dressing. Slice the blackened chicken cutlets and divide the slices evenly among the dressed salads. Serve immediately.