I nickname almost everything, even when I'm breeding, I'll have one male name and one female name, and I'll name them all. Even my HM slaves get names, usually they're joke names, but names, none the less. For my favorite pokemon I can spend up to a few hours coming up with a good nickname for them.
I never nickname Pokemon unless it was a repeat run of a game that isn't the 3rd version, either by Nuzlocke'ing it or by playing the opposite game a few years after they originally came out.
Not that devout to Nuzlocke runs though, i'll purposely avoid popular Pokemon such as starters, Lilligant, Krookodile and whatever and try to use things like Sigilyph, Mawile, Kangaskhan and whatever...most latter was cool in HGSS....in fact it's a good game to Nuzlocke, just because of the Pokewalker's tendency to spit out unusual Pokemon, felt really godly with a female Kangaskhan with Scrappy, i'll let the people decide if a level 5 Pokemon that obeys you is overpowered considering its natural strength as a single-stage pokemon.
RSN: Plucky9, Total: 2444. KoL: Plucky, currently a Pastamancer ACNL/3DS FC: 4897-5920-6758 Ricky of Farm