Steep onion: Add vinegar to the bowl with the onion and let it rest for 10 minutes.Discard the vinegar.
Mixing salad: Combine the onion and the remaining ingredients in a large bowl. If you won't serve right away, cover and keep chilled for later.
Serving: This salad keeps refrigerated for about a day. Once chilled, serve right out of the fridge so the mayonnaise doesn't spoil.
Video
Notes
The potatoes should be boiled beforehand with a teaspoon of salt added to the water, or you can use leftover boiled potatoes from another meal.Both mayo and rotisserie chicken already have salt, so I did not need to add salt to the salad. Taste and salt to taste if you find it necessary.Served as a light meal, this serves 4, as a salad, serves 6.