Fall In Love With This Easy Marry Me Chicken Salad

Name: Fall In Love With This Easy Marry Me Chicken Salad
Ingredients: 1 cup mayonnaise; 1 1/2 tablespoons Dijon mustard; 1 tablespoon sherry vinegar or red wine vinegar , optional; 2 teaspoons garlic powder; 2 teaspoons dried basil or oregano; 1/2 teaspoon kosher salt , plus more to taste; 3/4 teaspoon freshly ground black pepper; 1 (7-ounce) jar sliced sun-dried tomatoes packed in oil; 3 cups (about 1 pound ) shredded cooked chicken; 3/4 cup grated Parmesan cheese; 1 large shallot , finely chopped; Fresh basil leaves , optional