Spread each apple ring with peanut butter, then sprinkle with the chopped nuts.

Melt the chocolate in a microwave-safe bowl in 20-second intervals, stirring between each, until smooth. Transfer to a small resealable plastic bag and snip off one corner.

Drizzle the melted chocolate over the apple rings.

Transfer to the freezer and chill until the chocolate is set, about 1 hour. Serve cold.