Even though my main hobby is cooking I don't usually make desserts, but faced with your problem here's something I would try. Feel free to make any adjustments (if you think they're good you might like to post your changes on here). Mix some plain cocoa with a little of your sweetener of choice, place in a soup plate or similar vessel. Now, using your choice of low carb nuts - almond, hazel, brazil, walnuts, etc., melt a knob of butter in a small pan, enough to coat all the nuts, then remove the nuts with a slotted spoon and place them in the cocoa mixture, rolling them around until they are thoroughly coated. Remove them from the cocoa mixture and spread them out on kitchen paper.
They might be a bit messy to eat as you're going to have cocoa all over your fingers, but this snack will be a lot lower in carbs than 43% sugar-coated ones.
Can anyone improve on this idea? There's nothing like getting several brains working on a problem.
Good luck.
Just had another thought - you can buy 85% chocolate (low carb), or 70% if you prefer it slightly sweeter, (Aldi do a great line in chocolate of this type at a great price). First spread a length of cling film on a flat surface (a baking sheet, a chopping board, etc.), then melt some chocolate in the microwave using a Pyrex dish. As soon as the chocolate is melted, remove from the microwave, drop in the nuts of choice, stir to make sure each nut is coated, then spread the nuts out on the cling film, making sure the nuts don't touch. Place in the fridge until the chocolate is set. That sounds an improvement on my first idea. If you try it, let us know here, please.
