Hi. My friend has a Yorkie and she gets that snorting attacks when she gets to exited and or scared. I have not yet experienced that with my little one and do hope not to ever go through it though. It is very scary.
What my friend does, upon instructions from the vet, is stick her finger in her Yorkies mouth and hold down her tongue, then she gently blows in her nose and about a minute or not even and her Yorkie stops with the fit. They call it anxiety attacks. Can you believe it Yorkie' also get it. Try it, maybe it works with your baby. I do wish you the best and hope that it is nothing serious.