Heat the oil in a skillet over medium heat for 1-2 minutes. Cook chicken until meat is no longer pink, about 5-7 minutes per side. Chop the cooked chicken into small pieces (no bigger than 1/2-inch cubes). Place in the refrigerator to cool for 5-10 minutes.
While the chicken is cooling, place the remaining ingredients in a mixing bowl and stir to combine. Season with salt and pepper to taste.
Once cooled, add chopped chicken. Serve as a side dish or in sandwiches.