In a small saucepan, whisk together coconut milk and cardamom. Add orange peel and bring just to a simmer. Remove from heat and let stand 15 minutes.

Line a baking pan with parchment. Set aside.

Return coconut milk mixture to heat and bring to a boil. Place chopped chocolate in a metal bowl. Remove cream mixture from heat. Pour cream through a fine-mesh sieve set over the chocolate (discard solids). Stir chocolate-cream mixture until melted and smooth. Sweeten with stevia.

Pour chocolate mixture onto the unlined baking pan, and spread in an even layer with an offset spatula. Transfer baking pan to freezer; chill chocolate until hardened but malleable, 15 to 20 minutes.

Using a tablespoon, scrape enough chocolate from pan to form a roughly shaped 1-inch ball, being careful not to press too hard against baking pan. Repeat. Transfer balls to the parchment-lined pan; chill truffles in the refrigerator 10 minutes.

Place the powdered erythritol, cocoa powder, and the chopped pistachios in three separate bowls. Roll the truffles in desired coatings.

Store in an airtight container in the refrigerator.