Following the other around and nibbling on each other is normal, one trying to cuddle with the other can also look like chasing, but if it's truly chasing, trying to corner it and pecking hard not just nudging/nibbling that could be a problem. Are they still in the incubator? If so the older one might be hungry. I'm not an expert by any means but if you can take a video and up load it to you tube or another video site and post a link, I may be able to distinguish if it's agressive or normal behavior. Or someone else might come through that's more knowledgeable.
