Night terror? Nightmares? 1 year old

Maybe just 2 hours after my boy fell asleep I was awakened by hearing him sniffling (the kind of breathing that occurs normally after a sob fest). He was still very much asleep and then after a bit started crying badly. He only calmed down when I held and nursed him (still asleep). This went on for about an hour or two until he finally slept silently with some regular tossing.

This has happened maybe a couple times prior random nights. Why would this happen? Can 1 year olds have nightmares or night terrors? What could be going on?