There are a few ways to get a Persian without nicknaming it:
1) Evolve a Meowth. You may have to take measures if you want a specific Meowth form (Kantonian, Alolan, or Galarian). It evolves at level 28.
2) Trade for it. You can request a Meowth or Persian that hasn't been nicknamed. In fact, if you want to trade for one, just let me know. I never nickname my Pokémon.
3) If you already have a Meowth or Persian with a nickname, breeding it will give you a new Meowth without a nickname that you can evolve into Persian.
It's important to note which era of games you're trying to get it in. A Kantonian Persian is hard to obtain in Alola, and the same is true of Kantonian and Alolan Persians in Galar. Speaking of, if you want it in Sw/Sh, I'm unable to trade it to you since I haven't got a copy of the Nintendo Switch just yet. But I'm willing to trade for one in Kalos, ORAS, or Alola.