When I was younger I didn't nickname my Pokémon, but as I got older I started to do it. I realized that it adds personal charm to every playthrough, and it's fun. I tend to stick to nicknames that are either puns, references to other games or characters, or food-themed names. I definitely develop a closer bond to my Pokémon as a result. It's a special attachment that transcends the generations. For example, to this day I always nickname any Mareep I use in any game Sherry (a pun on shearing a sheep's wool) and every Shroomish I give the nickname Goomba (that one should be obvious lol) to me, every Oshawott is called Sushi 


 from my first playthrough of White all the way to Legends: Arceus
I still remember playing Pokémon Ruby for the first time. Torchic was my very first Gen III starter because May had one in the anime, so I wanted to use one, too. I was a silly kid who was obsessed with the anime lol it's actually why I chose Piplup as my Gen IV starter when I first played Diamond, since Dawn had chosen Piplup to be her partner. But really, Turtwig is my favorite Gen IV starter. I began choosing my starters based on my own personal tastes and preferences.
Neither of them had nicknames, so they were just called TORCHIC and PIPLUP, since the older games used ALL CAPS for every POKeMON.