Haven't really thought of nicknames yet, I suppose I might as well. Team plans (so far), also I like to always have close to 6 pokemon so in-between coming upon them I'll have interrum members:
#1: Fennekin (Fire ->Fire/Psychic?) - I kind of want to know what its evo looks like before I name it, but I'm thinking Sahara (F) or Mohave (M). Something desert related.
#2: Flabebe (Fairy) or Spritzee (Fairy) - I think I'll start out with one and then switch for the other later in the game, depending on which I run into first. For Flabebe, maybe Delilah(F) or Dahlia(F), not sure about male name. For Spritzee, Flamenco or Fandango (M) are contenders, also Fuchsia (F) and Festoon (F).
#3: Helioptile (Normal/Electric) - Not sure yet. I'm sure I'll think of something good by the time I get it. Maybe Solara (F) or Sol (M). But, you know, better. I'll think of something. I want it to be sort of cute-sounding and related to the sun.
#4: Orotto (Grass/???) - Apparently this is a creepy dead spider tree pokemon that might be dark/grass or ghost grass, therefore it's on my f*cking team no matter what, because that is awesome. No idea about names yet.
# 5: Honedge (Steel/Ghost) - Pretty sure this is going to be genderless. A sword-related name like Gladius, Spatha, Zatzbalger or Zweihander is definitive.
#6: Fletchling(Fire/Flying), later to be traded for Noivern (Dragon/Flying) or it's prevo, when I run into it. Again, no idea about names. For Fletchling, maybe something related to the color red, Scarlet(F) or Crimson(M), maybe? Noivern, something cool-sounding and gothic, like Grotesque or Gargoyle (M), or Phantasmagoria (F) if it will fit.
Hmm, if Fairy doesn't turn out SE against Dark, then I think I need a bug or fighting type on my team. With two Ghosts, a Dark type will wreck me at this point. Maybe pick up a water type, if I come upon a good one, new pokemon or not.
My plan at this stage is to give them all human names that start with the same letter as the Pokémon's name. I did that in White 2 with the final stage's name (ie. Soren for Serperior Amelia for Ampharos, Makoto for Magnezone, etc.).
However, since only a few 'mons have been revealed, I will settle for the base stage's names. For example, my Froakie shall be named François (or Françoise if female). I'll name the others as I capture them.
I probably won't name anything for the first few playthroughs so I can learn the names. I've given up on learning a lot of town names by this point, but the actual pokemon names I still need to know. And when I do nickname, I like it to be impulsive, and not put too much thought into it. Keep them fun.
I'll only be going with my starter for a nickname definitely, and I'm waiting on the evolutions to be revealed so I can better pick one, like I did with Chimchar (Inferno) and Tepig (Torch Hog). Others will depend on when I get them.
I'll be naming pokemon for both of the games, as I get them , as a spur of the moment thing.
I'm naming my Fletchling/Talonflame "Songbird", after the character in Bioshock Infinite. Then I might name my Fennekin "Booker", also after a Bioshock Infinite character. If I ever get a Sylveon (which I'm hoping will be male), I'll name him Louis.
Gonna name them all names derived from French artists.
What I do is play the first games of the generation, learn the Pokemon, then when the third or sequels come out I start giving them funny nicknames. Except the starter. And legendary.
I wanna make mine more of a in the moment decision, but I've already thought of a few that I'll probably use. Possibly Flint for Fletchling because flint was a common stone used for arrowheads by Native Americans and Fletchling is based on an arrow. Plus, Flint was a Fire type user in Sinnoh, for good measure. So Flint is almost certain for Fletchling.
Honedge will probably be a sword based nickname. Dunno what though.
In my most recent play throughs of LeafGreen, Emerald, and Platinum, I named my Pokemon after Star Wars characters, random anime characters, and Smite gods respectively, but for X or Y I will probably just make bad puns since I can't think of anything better at the moment.
I like to playthrough first, usually pretty blind (I mean, I know the Pokemon but I won't go looking up locations or plot details). So no nicknames until I get used to their names. Then I do a second/main playthrough where I do search for specific things with nicknames, usually punny or just names I like.
Swirlix will be Fluffpuff just because. All dragons shall fear Fluffpuff.
I don't nickname much, but because I like Monorpale, Fennekin, Noivern and Talonflame so much, I'm thinking of nicknaming them 'Excalibur', 'Mozilla', 'Gigahertz' and 'Vulcan', respectively.
I usually name my team after various off-the-beaten-path dieties or historical figures, except my Magmortar, who is Urusai (Japanese for annoying and other concepts around it, I fail at trasnlating that word). He just wouldn't stay in a Great Ball when I was getting him as a Magby. My Lucario is Enos, Vaporeon is Nodens (an old Celtic water god), Arminius is my Gallade (some gladiator who was famous but no one cares about him now like they do Spartacus)
I haven't really formulated a team yet for X, though Xerneas is a legendary I would actually use. Maybe I'll start using the names of the fairies in a Midsummer Night's Dream...