>>29905383If it's caught in the same way as the UBs like people are saying, it'll be a possible random encounter in a single area once you've caught all 10 UBs in their missions. I think someone said its location was Ten Carat Hill.
I'm working on gathering synchronizers before I get to catching, but the 1 Nihilego is in either Wela Volcano Park and Diglett Cave, and the 4 Pheromosas are in Verdant Cavern after that.
Oh, and you now have the option when obtaining pokemon with a full team to either send new captures to the box automatically, or see the option to add them to your team and/or view their summary, so it saves a little time of flying back to a box.