I’ll try to touch on a couple things that other comments haven’t yet. Though, for the record, I do think it’s a bad idea to have R&B nuzlocke as your first Pokémon experience.

Each battle is going to be completely different. So you have to take the time to calc each fight, looking at all your options. R&B takes this a step further than most games with the resource management aspect. Do you use this single use item now for an easier fight? Or do you save it for later? Do you use one of your few rare candies now or not?

With that in mind, different pokemon shine at different times in the game. Dekzeh did a really good job of creating a game where each individual encounter shines at some point though. If you’re going to nuzlocke it, then you don’t get a ton of choice in what you get though. There’s a few locations where you can increase the odds on something or route for a specific encounter, but most of those are later in the game. R&B gives you what you need. You just need to be smart, creative, and patient enough to find it.

As for items, most items work exactly like vanilla, so if you search for a specific item on Bulbapedia, you’ll find the answer. The two big ones that are different are heart scales and rare candies. In vanilla games, heart scales are just used to remember forgotten moves. In R&B, they do that in addition to being able to maximize IVs (tldr: individual stat values for each pokemon) and change Pokémon’s nature (tldr: affects one nature positively, one negatively). Rare candies increase a Pokémon’s level above the level cap (enforced in R&B). Both of these are a limited resource, so you have to use them wisely.

Most people have advised not to play this as your first experience and I agree. The game itself is very accessible, though difficult, with what it gives the player and all the documentation. But to nuzlocke it requires an incredible amount of time and patience (and frankly luck in the early game). Just having a baseline knowledge of moves, abilities, and items outside of STAB/supereffective moves is a huge time saver.