Melt the chocolate chips in the microwave. Place chocolate chips in an oven safe bowl. Microwave in 30 second increments to ensure the chocolate does not burn. (Example: Microwave for 30 seconds, stir the chocolate and then place back into the microwave.) Repeat this until the chocolate is completely melted.
Make sure the melted chocolate isn’t hot. Allow it to cool down a bit before making the mousse.
Add Greek yogurt, melted chocolate and cacao powder into your stand mixer bowl. If you don't have a stand mixer, you can use a hand mixer.
Use the whisk attachment and whip the mixture until combined and creamy.
Cover and place the mousse into the fridge for a couple of hours or overnight. It will get thicker as it sits in the fridge.
Scoop it into individual cups with a cookie scoop.