At what level should I evolve my nidorino?

Literally what the title says. I wanna evolve into a nidoking before gym 2 but i dont know at what level - im afraid I may loose a very powerful earth move.
Help anyone?

Possibly once it gets to a high level like around 45-50 or so idk

If you want to evolve your nidorino into nidoking, the level I would recommend evolving is 43. By then, you get access to Poison Jab, which is a decent poison type move, as a nidorino. At lvl 43 exactly, upon evolution, you will learn Earth Power. Nidorino doesn’t really learn any other noteworthy moves except toxic spikes, which you should get by then, and nidoking’s level up movepool doesn’t fare too much better. Either way, if you get past lvl 43, you should just be able to use a heart scale on the nidoking and heart scale are not too uncommon (can be gotten from breaking rocks). So, that is what I think.