For this achievement, you're going to want to be playing as a stealthy killer in order to get close to the survivors and without having them run away. I'd steer clear of Pig and Wraith for this one, as their ability to grab a survivor off a generator is a bit limited without the use of certain add-ons (in the case of Wraith, said Add-on needed is ultra rare) or perks.
The three killers I would recommend for this achievement are Spirit, Shape, and Ghostface. These killers all have very decent stealth abilities, but unfortunately for the most part their base kits aren't going to cut it: you're going to want to use some stealthy perks or add-ons for this one.
For Spirit, I would highly recommend the use of Prayer Beads: this Very Rare add-on completely eliminates the "whoosh" sound effect that plays when the Spirit is near you in the spirit world. This is super effective for getting generator grabs, as unless the survivor is running a perk such as Spine Chill, they will have zero idea you're coming until they're already on your shoulder. I'd also recommend using one of the variety of Duration increase add-ons for your power, so you can get to generators in the spirit world from farther away. Using the Doctor teachable perk Monitor and Abuse (which decreases your terror radius by 8 meters when not in a chase) is also helpful.
For Shape, I'd also recommend the use of Monitor and Abuse. Shape has the lowest terror radius in the game when he's in Tier 1 of his power, and Monitor and Abuse makes this terror radius fall to 0 meters when not in a chase, allowing you to walk right up to survivors and grab them. It's a bit less effective than Spirit, as a survivor can just use their camera to spot you approaching. For this purpose I'd also recommend the use of the very rare add-on Scratched Mirror: this add-on makes you unable to leave tier 1 of your power, but allows you to see survivor auras within 32 meters whilst stalking. Combining this with Monitor and Abuse allows for some pretty neat Generator grabs, and for you to scare survivors half to death.
And finally, for Ghostface, there are no add-ons or perks to particularly help you, as his power allows him to completely silence his terror radius and red stain just by activating it, allowing you to walk up to a generator and grab any unaware survivors that aren't paying attention. Getting generator grabs with Ghostface is really just a manner of playing Ghostface well and knowing how to stay hidden. The only ones I'd really recommend are the Add-ons that increase your movement speed whilst crouched: this allows you to maintain a low profile and gives the survivor less time to react to your approach.
Of note, however, is that all of the killers listed here are DLC killers. Whilst Spirit can be purchased with the in-game Iridescent Shard currency which you gain by leveling up, the others must be purchased with real money on account of being Licensed Killers. In the event that, for whatever reason, you do not have access to these killers, your best option will be using Wraith, and in particular two of his add-ons: the Ultra Rare Coxcombed Clapper and the Common "The Ghost". Coxcombed Clapper completely removes the sound of your bell, allowing you to uncloak in silence. "The Ghost" removes your terror radius and Red Stain for 6 seconds after uncloaking. Whilst this does seem like a powerful combination, actually getting into a situation in which you can ambush survivors effectively is pretty rare: most survivors will see you uncloaking and run, even without the sound. The best way to do this is to try to uncloak behind a wall really close to the generator, so you can pop out from the corner and hopefully get the drop on them.
For just some more general notes, the Hillbilly teachable Tinkerer removes your terror radius for a couple seconds once a generator is repaired to 85%, along with giving you a notification of that generator. The main problem, however, is that the killers mentioned here don't have any means of crossing the map quickly, except for Spirit, which can result in the perk running out by the time you even arrive at the generator (or the generator might even be completed before you arrive!). Only take this perk if you're seriously lacking in the ones mentioned in this guide.
Plague's Dark Devotion is an interesting one, as it transfers her terror radius to the obsession upon the obsession being hit, and your terror radius is reduced for 0 for a short time. However, much like tinkerer, this one can be a bit iffy: the obsession having the terror radius can cause more chaos than intended, and may actually result in survivors leaving generators as the obsession approaches. Plus, it does nothing to hide your red stain, so competent survivors will see you coming from a mile away.
I'd also recommend attempting this in the Higher Ranks: particularly from 20-16. Survivors here tend to be noob-ish and will prove more susceptible to these strategies than survivors at Lower Ranks. Be incredibly wary of survivor perks such as Spine Chill or Premonition, as these can reveal you coming even without your terror radius.
And just one final note: the map you attempt this on DOES make a difference: there are two maps in particular that work well for the purposes of these builds, and those are The Game and Lery's Memorial Institute. These maps have twisting and winding corridors, and often feature generators very close to doorways, meaning there's less time for the survivor to see you coming and flee. Avoid wide open maps such as the Swamp or the Red Forest: if you have offerings for the Institute or The Game, I'd burn those whilst attempting this achievement.