For vinaigrette-combine all ingredients and whisk thoroughly or shake in a jar with tight-fitting lid.
For chicken-Marinate chicken in 4T of the vinaigrette, for 30 min. Saute in med. skillet with small amount of additional grapeseed oil until no longer pink, 5-7 minutes. Remove from heat and cut chicken into bite sized pieces.
For salad-Combine greens, carrot, celery, tomatoes, grapes, apples and onion and toss. Divide evenly between 4 plates. Top evenly with chicken and sprinkle with mint and toasted nuts. Drizzle with the vinaigrette.