Many animal rights groups actually consider using similar deterrents as a legitimate training method. These could be sour and bitter sprays (Veterinarian's Best Bitter Cherry Spray, Grannick's Bitter Apple), or hot sauce like in your case. read more
Also, feeding your dog hot sauce knowing he gets an upset stomach and it causes him discomfort is absolutely a form of abuse. It’s not the proper way to train your dog to stop eating your food or nipping. read more