Tip: Since I'm assuming you haven't done the first gym yet, train up your Raboot, so it can kill those Grass Types with Super Effective Fire STAB.
Second Tip: Replace your Ninetails with something else, and you want variety in a Nuzlocke, and Cinderace is already a Fire Type, unless of course, it's Alolan, then keep it, but I don't think it is, since you didn't say that, so that means, you should replace it. A Weavle would be good, it covers both of your uncovered typings, Flying and Psychic, doesn't type overlap, and has good stats for a nuzlocke, fast, powerful, and decent Defenses and HP, also, it's only available after most of the gyms that are super effective to it. replace it with Weavle, all it's weaknesses are covered, and the Razor Claw is a hidden item on the island in the base of the Dusty Bowl. NOTE, THE FIRST TIME IT'S AVAILABLE IS ON ROUTE 8 ON THE STEAMDRIFT WAY. If you don't get it there, check here for the other times it's available in SWSH.
Okay, so out of those two, I'd go Barboach/Wishcash, because of the fact, that, once you've cleared the first gym, there isn't really any big Grass Type battles, unless you picked Sobble, which you didn't. It also has good HP, average of everything else, and a better typing than Claydol. It also evolves faster. It has better Attacking STATs and HP Stat than Claydol as well, and ingame, it's good to be Offensive, especially when in a Nuzlocke, since then you'll take 'em down before they can do the same to you, and you lose that 'mon forever. Claydol does have better defenses, but it also has like 6 weaknesses, making them kinda useless, something not good in a nuzlocke at all, especially when 5 of them have gyms that correspond, and the 6th is the other typing of a few Pokemon in the gyms.
Source: Experience in Nuzlockes, and the pages for these two, as well as the Serebii page of SWSH Gyms.
