In a large bowl, combine the shredded chicken, mayonnaise, sour cream, celery, red onion, parsley, lemon juice, salt, and pepper.
Mix well until all ingredients are well combined.
Toast the bread slices lightly.
Lay the lettuce leaves on top of the bread slices.
Spoon the chicken salad on top of the lettuce leaves.
Top with another slice of bread.
Cut the sandwich diagonally across.
Serve and enjoy!
