The Ascent

Use a tactical or augmentation to apply stasis to an enemy. The targeted enemy will be immobilized for a moment. During this, you will need to inflict enough damage to this enemy that it will overcharge and explode. To unlock the achievement you need to kill a different enemy using this overcharge explosion.
Early in the game, you can buy the "stasis drone" at the cyber vendor in Cluster 13 for 22,000 uCreds. There are probably different pieces of equipment you can use, but I think this is the earliest one you can get. Once you have this (or a different one), find a group of enemies close together and use it. In the case of the stasis drone, you can use it with when the tactical charge is full (fill it by causing damage to enemies).

To make it easier, use this on a group of low-level melee enemies as they will typically run at you, e.g. the Feral enemies in the deepStink location. Of course, this will work on most (not all are susceptible to stasis) other enemies as well. Next, try to damage only the enemy in stasis while keeping at least one different enemy alive. The overcharge explosion should kill the low-level enemies, or else you can help by damaging them a bit before the overcharge explosion.

I have included a short clip to show overcharging Feral enemies in the deepStink using the stasis drone.
I hope this helps. If I can improve upon this guide, please leave a comment.

You can pick this one up fairly early.

You'll need to have a Stasis Drone equipped in your Tactical slot (can be purchased in Cluster 13 from the Cyber Vendor for 22K credits if you don't find one), hit something with it, and continue shooting at them while the effect is active. You'll know you've hit someone when their health bar changes to a light blue instead of red.

As you shoot, an additional bar will appear over their health bar, indicating how much charge they've absorbed. Fill that, and they should start spraying out lightning bolts in all directions.