Warning: SPOILERS for Agents of SHIELD season 7, episode 7.
How has Nathaniel Malick survived his backfiring powers in Agents of SHIELD season 7? The SHIELD team may have apparently defeated the Chronicoms, but the MCU timeline has still been changed - apparently for the worse. Some of the changes are disturbingly personal, including the fact poor Mack lost his parents in 1976.
The most dangerous changes to the timeline, however, involve the Malick family. Wilfred Malick was supposed to die in 1970, and shortly after his youngest son Nathaniel was sacrificed in a Hydra ritual that transported him to the planet Maveth. The Chronicoms kept Wilfred alive for another six years, though, and although he was killed by Deke his son Nathaniel was never sent to Maveth - and remains a force to be reckoned with. Even worse, in 1976, Nathaniel Malick successfully transferred Quake's powers. SHIELD believed he had been died, or at least badly injured, when his newly-acquired powers backfired; but it seems that wasn't the case.
Agents of SHIELD season 7, episode 7 revealed Nathaniel survived, and by 1983 he had entered into a partnership with the last surviving Chronicom, Sybil. Malick is only shown briefly in the episode, so it's difficult to say just how much control he has over his Quake powers - but they're certainly not flaring as they were in the previous episode. This is particularly impressive given he would have lacked the support of the Inhumans, who helped Quake understood how to control her abilities and avoid breaking her own bones with them.
That isn't to say Nathaniel will have been without help, though. It's unclear how closely he is with Hydra, but he's likely still in close contact with Daniel Whitehall, their expert on all things Inhuman. What's more, Hydra remain active at a high level in SHIELD from 1976 through to 2014's Captain America: The Winter Soldier, so Nathaniel would have access to almost unlimited resources in order to figure out how to control the Quake powers. Furthermore, he also potentially has knowledge from the Chronicom Sybil.
The key to controlling the Quake powers lies in emotional self-control. The Inhumans taught Daisy to center herself emotionally, and only once she had done this was she able to use her abilities without the gauntlets. That point was driven home in Agents of SHIELD season 4 when a grief-stricken Quake went rogue and even had something of a death-wish. Her mind was a mess, and as a result her powers were tearing her body apart; as she worked through her heartache, she regained control of her abilities. Presumably Nathaniel has learned how to center himself as well, but he'll need to keep a handle on his emotions. That may be especially the case given Quake's powers were boosted in Agents of SHIELD season 5, apparently permanently, and Nathaniel may already be operating at that high power level. If so, he has the potential to crack the planet like an egg, and he could well be one of the most dangerous foes SHIELD has ever fought.