While it is possible to use cocoa powder instead of sugar-free chocolate chips, it will require some adjustments to the recipe. For every ounce of sugar-free chocolate chips, you can substitute with 3 tablespoons of unsweetened cocoa powder, 1 tablespoon of a keto-friendly sweetener, and 1 tablespoon of fat (such as butter, coconut oil, or ghee). Remember that this substitution may result in a slightly different flavor and texture, so you may need to experiment to achieve the desired outcome.