Toast nuts quickly in a dry skillet over medium-high heat. Stir frequently, and as soon as they become fragrant, remove the nuts from the pan. Set aside.

Bring broth to a boil in a medium saucepan; gradually stir in couscous. Remove from heat; cover and let stand 5 minutes. Fluff with a fork. Spoon couscous into a large bowl; cool slightly.

Add chicken, onions, radishes, cucumber, parsley, and pine nuts; toss gently to combine.

To prepare dressing, combine vinegar and remaining ingredients, stirring with a whisk. Drizzle dressing over salad; toss to combine.