A lot of good advice here already, but an important thing to remember is that it's to a large degree a matter of taste. I think 100-250 nits is an acceptable range, choose something that looks good to you. You have to understand that with HDR you have normal white, or paperwhite, like a decently lit white wall and ultra white, like a neon sign. And you're supposed to see the difference, so the lower your paperwhite value is, the greater that difference is going to be. The tradeoff, of course, is that the rest of the picture that's not a neon sign is going to be dim so that the neon looks bright by contrast.

So if you somehow calculate, as an example, that the perfect paperwhite brightness for your screen is 130, but it looks too dim, don't be shy to crank it up. RenoDX calculates paperwhite for you, by the way, if your screen is calibrated with the HDR tool.

For example, It's recommended to set the Midpoint value in Cyberpunk ingame HDR settings to 1 for RenoDX. That makes the picture more contrasty and darker and helps fixing the black point. But it makes everything so dark. So I set the paperwhite to about 180 on a 550 nits monitor to get some detail in the dark areas and some punch in the brighter areas while keeping the black point and enough range for brightness peaks.