BEST Chicken Salad - The Daring Gourmet

2 large boneless ,skinless chicken breasts cooked in lightly salted water then chilled in the fridge and diced, about 4 cups (for the best texture, avoid canned chicken) 1 cup chopped celery 1 1/2 cups halved seedless red grapes 2 tablespoons toasted sliced almonds or toasted chopped pecans , optional for some crunch 3 green onions , chopped 1 cup mayonnaise (for a healthier choice use Avocado Oil Mayonnaise) 1/2 cup sour cream 1 tablespoon lemon juice 1 teaspoon prepared yellow mustard 2 tablespoons chopped fresh parsley 1/2 teaspoon dried dill weed 1/2 teaspoon onion powder 1/2 teaspoon garlic powder 2 teaspoons sugar 1 teaspoon salt 1/2 teaspoon freshly ground black pepper