Pat the chicken breasts with a paper towel.
Drizzle olive oil and blackened seasoning on top of the chicken. Rub until all of the chicken is coated.
Heat a large skillet over medium-high heat. Add 1 tablespoon of olive oil.
Add the chicken breasts and cook for about 7 minutes on each side depending on thickness. Cook until an internal temperature reaches 165 degrees F. Transfer to a cutting board, let rest until ready to slice and serve.
Make the dressing by whisking together all of the dressing ingredients (except for the olive oil). Gradually add in the olive oil and whisk until smooth. Season with salt and freshly cracked black pepper to taste.
Make the salad: add the lettuce to a platter, top with sliced chicken, radishes, and avocado slices.
Drizzle the dressing over the top. Sprinkle with chives.