The following combination of views seems a natural one to me, but (in my admittedly limited excursions into the field) I have not yet seen it defended:
1. True epistemically normative statements are made true by objective facts.
2. These facts are naturalistically respectable facts, having to do with e.g. the truth of the subject’s beliefs, or (better) their probable truth given her evidential position.
3. This does not mean epistemically normative statements are equivalent in meaning/sense to statements which are explicitly about truth of beliefs or their probable truth.
Cf. the corresponding view in ethics, that true moral statements are made true by objective natural facts about e.g. the maximization of utility, but do not have the same meaning/sense as statements which are explicitly about the maximization of utility.
Naturalism about epistemic norms often seems to get equated with the Quinean project; other options are not mentioned. I’d be interested to know if 1-3 are defended in some area of the literature that I haven’t yet managed to stumble upon!