1. Mix together sweetened condensed milk, butter, maple syrup and nuts. Gradually beat in sugar. Chill in refrigerator 3-4 hours (or for up to 2 days).
2. Roll into 1" (2.5 cm) balls. Keep refrigerated until ready to dip.
3. Melt chocolate in top of double boiler. Dip candy balls in warm chocolate. Place on parchment paper-lined baking sheets until set. Store covered at room temperature or in refrigerator.