Start by ensuring your roasted chicken breasts are fully cooled. Dice them into bite-sized pieces and set them aside. Slice your red grapes in half, chop the toasted pecans, and dice the celery and red onion. Chiffonade the basil by stacking the leaves, rolling them tightly, and slicing them thinly.
In a large mixing bowl, combine the diced chicken, sliced grapes, chopped pecans, diced celery, diced red onion, and chiffonade basil. Gently mix them together to distribute everything evenly.
Start by adding ½ cup of mayonnaise to the mixture. Stir gently to combine, ensuring that all ingredients are coated. If you prefer a creamier texture, add more mayonnaise, one tablespoon at a time, until you reach your desired consistency.
Sprinkle salt and pepper over the chicken salad to taste. Remember, you can always add more, but you can't take it away, so start with a little and adjust as needed. Mix well to incorporate the seasoning.
For the best flavor, cover the chicken salad and refrigerate for at least 30 minutes. This resting time allows the flavors to meld beautifully. When you’re ready to serve, scoop the chicken salad onto your choice of bread or rolls, and enjoy!
