So generally a teaspoon is 5g, making the carbs 0.7g, I used to add cocoa powder to things and it never effected me but I suppose it depends how sensitive to carbs you personally are so unfortunately its a question only you can work on finding an answer for through testing xx
One teaspoon (4g approx) of cocoa powder with a count of 14g carbs per 100g would work out at less than 1g of carbohydrate. If you want to know how that might affect your blood sugars the only way is to test before and after consumption
As the others stated, it's relative... If you were eating cocoa powder by the pound, it'd be a different issue. It's a teaspoon. It's probably got marginally less carbs in that the protein powder.
It's very high in oxalate if you care about that sort of thing, but from a blood glucose perspective you'd probably have to be chugging it back just to get the needle to move.