Here's another nickname, though not one that any of my Pokémon carries.
Cassandra or
Murphy for Absol: Cassandra is derived from the character of the same name from Greek mythology, the girl whose words were never believed but no less true. Murphy is taken from Murphy's Law; if something can go wrong, it's bound to go wrong, which fits in with the disasters that Absol warns of, but is instead accused of. It's bad for both Absol and the victims of the approaching disaster.
Now for a few Pokémon from my own games.
Raphnoldin the Venusaur: Rafflesia arnoldii corrupted and condensed into a single word. Venusaur's flower is at the very least the largest when it comes to flowers on Pokémon, especially its Mega Evolution.
Azulvura the Charizard: The name of my female Charizard in my OR game that Mega Evolves into Zard X. It's a combination of
azul (Spanish for blue),
sulphur (corrupted),
vuur (Dutch for fire) and the feminine suffix -a.
Thymouros the Salamence: Taken from the Greek words
thymós (anger) and
sfodros (vehemence; partly a reference to its species name). It refers to how violent and aggressive Salamence is made out to be in its Pokédex entries.
Saikyoufuu the Pidgeot: Combination of the Japanese words
saikyou (strongest) and
kyoufuu (gale), referring to Mega Pidgeot's Hurricane spam.
Caustikaizer the Beedrill: Derived from
caustic and
Kaiser (German for emperor). Mega Beedrill is one of the more successful Bug- and Poison-types (hence caustic) and easily one of the most hard-hitting.
Odysseus the Sharpedo: The name of the Greek hero who sailed the seas for twenty years before returning to Ithaca. An ironic name, as Mega Sharpedo looks like something that'd trouble seafarers such as Odysseus.
Schmolzra the Camerupt: Derived from the German word
schmelzen (melt), more notably the past participle
geschmolzen.
Shulk the Gallade: Mega Gallade is said to predict its foes' movements with its twin capes, much like how Shulk from
Xenoblade Chronicles can react to the visions granted to him by the Monado. On top of that, Mega Gallade's swords as well as the Monado are red.
That's it for now. If you've got anything to remark, feel free to just reply. Thanks for reading!