Preheat the oven to 350°F (175°C).
In a large mixing bowl, cream together the softened butter and powdered sugar until light and fluffy.
Add the sweetened condensed milk and vanilla extract, mixing until well combined.
Gradually add the flour, mixing until just incorporated. Stir in the chopped nuts and salt.
Roll the dough into 1-inch balls and place them on a baking sheet lined with parchment paper.
Bake for 12-15 minutes, or until the bottoms are lightly golden. Remove from the oven and allow to cool slightly.
While still warm, roll each cookie in powdered sugar to coat. Let them cool completely before serving.