1. Preheat oven to 350°. Bake pecans in a single layer in a shallow pan 8 to 10 minutes or until toasted and fragrant, stirring halfway through.
2. Whisk together mayonnaise, sugar, and vinegar in a large bowl. Stir in chicken, next 3 ingredients, and pecans. Add salt and pepper to taste. Sprinkle with bacon just before serving.