BEHOLD! A huge clusterfuck of my pony AU brainrot, featuring 14 different versions of Nuke!
I maybe need to stop making so many of these alternate universes...
Apologies in advance for the HUGE wall of text!

Nuclear Fission (235) is the original, a once-mad scientist that mellowed out after becoming a single father of 14 (9 of which he built through his Android Program).

Bright Future (232) hails from a utopian Equestria, one where ponies' best qualities are greatly exaggerated. He is meek and flighty.

Nuclear Dawn (223) is the reverse of Bright - worst qualities are more pronounced. He is vicious, cold, and holds the ambition to subjugate as many ponies and places as he can. One of the few with their own Android Program, rather than treat them as his own, they are a mangled, poorly-maintained cabal of sadists.

Halflife (294) comes from an Equestria where time as a concept does not exist. Due to this, the ponies have such inherently differing biology that they may even be considered their own species, fit with organs specifically made to withstand the violent back and forth of world events. He is a stallion of many regrets, frozen by the fear of being unable to make things right.

Nukette (233) hardly differs from the original Nuke and his Equestria; bar minute changes in specific details, and reversed genders, little changes. One thing for sure, however, is that rather than "mellow out the mad" upon becoming a single parent, Nukette maddened out the mellow.

Nuclear Powered (209) reverses the Android Program's numbers. Rather than Nuke having 5 children and 9 androids, 14 scientists came together to create a singular, near-perfect android. Despite being mostly components and code, Powered is by far the most well-adjusted of all of Nuke's alternate selves.

Final Flash (239) hails from an Equestria wracked by war. A distinctly unique political landscape with two primary superpowers and one ferocious, global terrorist cell, it mimics the world of Command & Conquer: Generals. Flash herself is the ponification of the Chinese faction's "Nuke Cannon" unit. She wields one herself, hauled along on a trolley, supported by her back. She has an almost cultish reverence for the weapon, caring for it meticulously.

Cold Fusion (003) resides in an Equestria of great scientific advancement. As his name suggests, he was greatly influential in the success of cold fusion energy, and is partially responsible for the technological boom. He's vain, snarky, and prideful to a fault. Sidenote, his Equestria's colors are somewhat reversed on the spectrum - darks become bright, warms become cool. He himself has a blue palette, rather than his counterparts' more common reds, yellows, and oranges.

Bombshell (226) conversely, has a less-advanced Equestria. Manehattan is not quite the sprawling urban jungle it will eventually become, and many other technologies are just making their first debut. Bombshell herself is a cunning, flirtatious assassin who frequently feigns as a well-known adult escort. Though it's a ruse that lets her get very close to her targets, many times she can't help but.. enjoy the work.

Polyatomics (210) is further back still - in fact, she was the one in her universe to discover atoms, and by extension, radiation as a concept. Despite all of her monumental breakthroughs in her fields, she's difficult to speak to, being a poor conversationalist. She holds herself in such high regard that she's begun seeing others as below her, and resents the difficulties of social interaction. Whether or not she realizes she causes most of those difficulties is yet to be seen.

Ballistic Borderline (237) is a pegasus war veteran turned labcoat. In his dimension, the Mane 6 had never been around to stop Sombra's return in the Crystal Empire, and the 1000-year-old war continued. He's a rocket scientist pioneering intercontinental ballistic missiles, and is a part of Equestria's very own Manehattan Project. He is touchy, angry, and wrought with the traumas of war.

Windscale Ash (131) is a kirin born and raised in Ponyville long after Twilight has taken the throne. Luster Dawn and her friends form this world's Elements of Harmony. Windscale herself has assisted them on occasion, crafting trinkets and gadgets that don't always work to try and help them on their travels. Her flames are far ashier than most kirin. Though her cheery disposition and optimism make it difficult to get her to turn into a nirik, once she does it's very difficult to calm her down.

Midnight Clockwork (057) is Queen Nightmare Moon's very own Royal Engineer. With the Mane 6 having never met, Nightmare Moon was free to overthrow her sister upon the breaking of her imprisonment. Midnight is a strict, no-nonsense, high-class stallion. He feels little for those under him, and even less for those that reject his Queen's rule. His current project is an attempt to use radioactive material as a long-lasting fuel source for various machines.

Nucleus (040) the changeling is a traitor to the Hive. With the Mane 6 out of the picture, Queen Chrysalis succeeded in her invasion of Canterlot. Nucleus, along with Thorax and a scant minority, rejected the Hive's brutality in favor of assisting Zecora's rebellion. He is nervous, paranoid, and skittish. The talisman he wears is a symbol of trust; the runes etched into the stone prevent him from disguising while he wears it.