Follow these steps once you have added your ice cream in the ice cream maker, but before it is processed into ice cream.
Melt the chocolate in a bowl over simmering saucepan of water (also called a ban marie), or melt the chocolate in the microwave on a low setting until most of the chips are melted.
Once the chocolate is melted, remove it from the heat.
With a slim fork or other utensil, drip chocolate in streams into the ice cream bowl in small intervals, and immediately stir the ice cream to break up chocolate. It will solidify as it hits the ice cream so you want to add it in slim streams to avoid big chunks of chocolate from forming. I either stir the ice cream with a knife in-between each chocolate dripping, or I add the chocolate drizzles while the ice cream maker churns.