Bring a large skillet of salted water to a boil. Reduce to a simmer.
Add the chicken and ¼ teaspoon pepper. Cook, covered, until the chicken is cooked through, 8 to 10 minutes. Remove the chicken and, using 2 forks, shred.
Toss the chicken with the carrots, pecans, mayonnaise, raisins, parsley, lemon juice, ¾ teaspoon salt, and ¼ teaspoon pepper in a medium bowl.
Serve the chicken salad on top of the lettuce and with the buttered toast on the side.