Nicknames!

[SirBlaziken]

^ No, it's 9 letters, you're good.

[Captain Jigglypuff]

^Nicknames can be a bit longer now.

[Hahex and Oshawott]

I don't usually nickname pokemon but this one I'm a little proud of.
It's Astronaught the Chesnaught! i am a genius, ladies form a queue

[Captain Jigglypuff]

I named a male Jigglypuff Iggy Puff. Also named my Throh Up as a joke.

[ZD| Wattmole]

I nicknamed my Klefki, Lowkey. You know Lowkey? The Trickster God? I can see you were so confused because he's real...low key.

I'll just let myself out...

[Zubatman]

I used to Nickname my Pokémon after other Video Game Characters, Examples are:

Scizor--Zero (Mega Man Franchise)
Zangoose--Zangief (Street Fighter)
Seviper--C. Viper (^Same as above)
Electivire--Blanka (^Same as above)
Smeargle--Max (Scribblenauts)
Ditto--Kirby (Kirby, obviously)
So on...
Lately I have been naming my 'mons after previous Gym Leaders

Charizard--Blaine (Kanto, Fire)
Aurorus--Pryce (Jhoto, Ice)
Raichu--Lt. Surge (Kanto, Electric)
Lapras--Misty (Kanto, Water)
Roserade--Gardenia (Sinnoh, Grass)
Venemoth--Koga (Previous Kanto, Poisen/Current Jhoto Elite 4)

[Delicious_Scout]

I used to Nickname my Pokémon after other Video Game Characters, Examples are:

Scizor--Zero (Mega Man Franchise)
Zangoose--Zangief (Street Fighter)
Seviper--C. Viper (^Same as above)
Electivire--Blanka (^Same as above)
Smeargle--Max (Scribblenauts)
Ditto--Kirby (Kirby, obviously)
So on...

I see I am not alone, at least up to some point:

Hariyama - E. Honda (Street Fighter)
Xerneas - Valentine (Skullgirls) Because of her eye(s). The cross.
Greninja - Rannana (Pokémon) Rana is frog in Spanish, but this Pokémon is way better than Rattata (sorry, Joey).

Some others are related with trolling:

Hippowdon - Hitrolldon
Rotom - Rotrollolo (lololo, lolololo ♪♫)
Durant (with Entrainment and Truant) - Trollant
Female Garchomp (with Iron Head and Sand Veil) - Sandyhax

And others are just from the Internet:

Lapras - 1337pras (Leetpras)
Charizard - Híper Dolan ("Híper" is Hyper in Spanish LOL GENIUS GT*O OF MAH LOGIC)
Snorlax - GabeN
Mewtwo - Mewtwo: Ep.3 (Confirmed)

[Hitmonchu]

Nicknamed Pokemon in my team:
Waffles the Greninja: What can I say? I had a craving for waffles when I chose my starter xD
Maurice the Charizard: Dunno, just liked the name Maurice, especially for a Charmeleon.
Mustard the Zygarde: It's a freakin' legendary, so I wanted to name it something cutesy
Sweetheart the Lucario: I have a soft spot for dogs, okay? XD

[Lion Demon]

Poke-transporter has changed so many of my Pokemon's nicknames that it just makes me 

[ShinyNinetales]

Mega Absol: Kirby (His ability will come Right back at 'ya!) it's punny

[Mew King]

Poke-transporter has changed so many of my Pokemon's nicknames that it just makes me 

Were you like my friend who had "Fatass" the Slowking?

[CORPORAL]

Stoutland - Ryuu

Gengar - BIG BOY

Serperior - KusanoHebi

Zebstrika - Kradness

Charizard - Kasai★

Druddigon - Kowaii★

[SirBlaziken]

Pidgeot - Bird Jesus

*Falls on the floor laughing*

[RichieL1991]

My favorite Nickname to give a pokemon was always nicknaming my Slowbro "Pink Floyd" 

[Danatales]

lessee this is my y team of named children:

Delphox- Bellatrix (female)
Dragalge- Thrax (male)
Mawile - Laurie (Female)
Manectric- Jonathan (male)
Garchomp - Jaime (male)
Noivern- (Vic)

literally half of them are named after band members ooPS

I dont theme nickname much anymore other than things like that, but I do name all my Eeveelutions after Las Vegas casinos because idk it sounds cool 8U (except for Slyveon, which I named Liberace ahahaaaa)