Peel and chop the avocados. Place in a bowl and sprinkle with 1 tablespoon lemon juice.
In the bowl of a food processor, combine mayonnaise, sour cream, parsley, minced garlic, a quarter of the diced avocado, the remaining lemon juice, and a little salt and fresh ground black pepper. Blend until smooth.
Chop the cooked and cooled chicken and transfer to a large bowl. Add the bacon, green onion, remaining diced avocado, and the dressing, and gently fold the mixture together. Season with additional salt and pepper, to taste.
Serve on sandwich rolls, on toasted whole wheat bread, or roll it into wraps.