Any breed can turn nasty. Dogs are subject to most of the diseases and conditions and environmental influences that can cause humans to turn nasty. But chaining a dog does not turn it nasty, unless it is almost a wild dog that has never been penned, chained, or restrained in any way.
Please read the article I linked in 87. There are reasons frequent chaining is a bad idea and chained dogs are frequently involved in bites. As I said some breeds are less likely to bite, but chained dogs are more likely to bite. It seems to be a cause. If you have a dog, find another way to keep it from wandering.