In a large mixing bowl, combine the mini marshmallows, shredded coconut, mandarin oranges, pineapple chunks, and maraschino cherries. Gently fold the ingredients together to combine.
In a separate bowl, mix the sour cream and vanilla extract until smooth.
Pour the sour cream mixture over the fruit and marshmallow mixture. Gently fold until everything is evenly coated.
If using, stir in the chopped pecans or walnuts for added crunch.
Cover the bowl with plastic wrap and refrigerate for at least 1 hour before serving to allow the flavors to meld.
Serve chilled, and enjoy this delightful salad as a side dish or dessert.