If you nickname your Eevee with the following nicknames below it will evolve into the Evolution of your choice.
Sparky = Jolteon
Rainer = Vaporeon
Pyro = Flareon
Note that due to server issues, "it is recommended to name your Eevee with your intended evolution name, then close and restart the app to confirm the name went through on the servers."
Source: https://www.destructoid.com/pokemon-go-psa-you-can-pick-how-eevee-evolves-375347.phtml
Sparky = Jolteon
Rainer = Vaporeon
Pyro = Flareon
Note that due to server issues, "it is recommended to name your Eevee with your intended evolution name, then close and restart the app to confirm the name went through on the servers."
Source: https://www.destructoid.com/pokemon-go-psa-you-can-pick-how-eevee-evolves-375347.phtml
