Alright, here goes my list, and this is what i nicknamed my Pokémon in the first gen games! I might do one about the 2nd gen when i feel like it!
These are the ones i like the best, by the way.
Bulba, the Bulbasaur -> Ivysaur -> Venusaur
I was pretty uncreative with this one, but i think it sounds nice!
[I also named Blastoise Bluey, after that walrus from Diddy Kong Racing and Charizard Draco, after that kid from Harry Potter when i was younger]
Nessie, the Lapras
I gave it to Lapras because it resembles the Loch Ness Monster, and "Nessie" was a nickname given to the "Loch Ness Monster", which was believed to be a Elasmosaurus that still lives to this day, roaming the Loch Ness lake.
SolidSnake, the Onix
He's a rock snake.. Rock solid, and a snake. Solid Snake.
Heavy Mole, the Dugtrio
I love Dugtrio. He has good Attack, Speed, can learn earthquake, sure, his design is silly, but don't judge a book by it's cover. He's awesome,
As for the nickname, i made it Heavy Mole because Dugtrio are 3 moles, and that reminded me of that hard boss from Kirby's adventure, "Heavy Mole", which looks like a Megaman miniboss rather than a mole.
But anyways, i love both of these things!
Tyson, the Hitmonchan
I never really liked Boxing that much, but i was obsessed with Mike Tyson's Punch-Out, so the first time i saw this thing on the Dojo, i named it Tyson, as a homage to my favorite boxer!
P.S Please don't give Tyson your ears. He'll bite them.
UriGeller the Alakazam
Uri Geller = A magician who likes bending spoons [He also sued nintendo once because he thought Kadabra was some nazist "poké-ification" of him.]
I thought the Kadabra thing was really dumb, but Uri Geller is cool, so i named Alakazam that!
Kanga, the Kangaskhan, and Roo, the Cubone
These both are named after Winnie The Pooh characters. Kanga, is a Kangaroo mother who takes care of Roo, some kangaroo kid. [not the kangaskhan kid]
I named them that because i love Winnie the Pooh, and i like the theory of Kangaskhan being Cubone's mother. Pretty creative!
I'm not that good with nicknaming, but i think it's fun and thinking of something to name your pokémon is really nice!