Mexican Spiced Mocha Minus Chili Powder
If you like spiced mocha made elsewhere then you are already having chili powder, so chances are you will like the recipes you would make at home. Substituting something else will change the flavor of the result you get, instead I would modify the amount and type of chili powder you use to get the amount of heat you get. There's a huge variety of chili powders available from very mild to hotter than pain itself, so try a mild chili powder and add less of it than the recipe calls for, if you want more heat add more or use a hotter chili powder.