This isn't as daunting as the achievement description makes it out to be. Create a new game using the following settings:
Start Era: Information
Game Speed: Online
Map: Continents or Shuffle
No Barbarians
Leave everything else as Standard.
I set Map size to Huge and City States to 24.
As per the achievement description, we need to up-base on the continent of Nena which takes a little luck as the maps are randomly generated. This is the hardest part of earning this achievement.
As soon as you start, settle your first city, start building a Spaceport district and set your research to Satellite - we want to research the Satellite technology as soon as possible as to uncover to entire map to see which continents we have. Once you've done this, use the magnifying glass above your minimap and set it to "Continents" which will then list the available continents on the map. If Nena isn't listed, restart your game and try again. If Nena is listed, continue on to the next step.
Using a Settler unit, build a city on the continent of Nena, making sure you're close to another civilization or city-state. Once you've done this, build an Aerodrome district with a Hanger, along with a Bomber unit. Then, in the same city, build 9 Observation Balloons and scatter them around your Aerodrome.
The final part is to build a Nuclear Device which requires the Nuclear Fission technology, so be sure to research this en-route. Once this is built, it's now just simply a case of selecting your Bomber unit and dropping said Nuke on any city (city-states also work.