Place pineapple and pudding into a mixing bowl and mix well.
Add mini marshmallows and all but 1 tablespoon chopped pecans.
Fold in whipped topping.
Refrigerate Watergate Salad for 4 hours or overnight- the marshmallows really puff up.
Serve with remaining chopped pecans or candied pecans on top.
You can serve this one immediately but its better if you wait a few hours to get really fluffy! This makes a pretty large bowl, I would say serving 8, but that is generous servings considering this is a rich dessert salad.