If using roasted chicken breast, remove from packaging and microwave with corn until warm, 1-2 minutes. Carefully, toss with remaining taco seasoning. Add to salad and toss to combine.
If using chicken breasts, pat dry and season both sides with ¼ tsp. salt and a pinch pepper. Place a medium non-stick pan over medium heat and add 1 tsp. olive oil. Add chicken breasts to hot pan, and cook until browned and chicken reaches minimum internal temperature, 5-7 minutes per side. Slice chicken into ½" slices and serve on salad.