Line an 8 inch square baking pan with a parchment paper sling.
Roughly break the pistachios and cashew nuts in batches, using a mortar and pestle, making sure to not powder them. Transfer to a bow.
Bash the cardamoms using a mortar and pestle, remove the husks, and then powder the seeds.
Break the white chocolate into approx. 1" pieces and place them in a microwave safe bowl. Add the condensed milk to the white chocolate.
Microwave the white chocolate and condensed milk mix, in 20 seconds increments, stirring the chocolate with a spatula in between each increment, until the chocolate has melted.
Add the cashews, pistachios, almonds and cardamom powder to the white chocolate mixture and mix well. Pour into the lined baking pan.
Let the mixture cool slightly on the counter and then refrigerate for about an hour until the mix is hardened.
Lift the hardened mix out of the pan and cut into squares or triangles. Store in an airtight container in the refrigerator for about a week.