For the chicken, first time I made this I used four 10 oz / 283 g cans of chunk breast meat in water, drained. It was 4 cups and very convenient. I have also made this with 4 cooked chicken breasts, cubed, which was also 4 cups.
Using a dry skillet on low heat, add the pecan pieces and toast for several minutes, stirring them and turning them with a spatula often until lightly golden and fragrant, remove from pan and set aside to cool. If you are using pecan halves, just coarsely chop after toasting them and let cool.
To a large mixing bowl (I used a 4 quart bowl), add the prepared chicken, grapes, celery, onion, and the cooled pecans. Toss together.
To prepare the dressing, add all the Dressing ingredients to a small bowl and mix together.
Add the dressing to the salad, stir until well mixed. Cover and place in the fridge until serving.
Just before serving, mix in the cheese if using that, serve as is as a main dish with light sides of your choice.
Serve over lettuce or arugula. Recommended.
Serve in a large croissant with arugula. Highly recommended.