Is there a diacritic in IPA for explicitly marking a nasal consonant as orally released (like coda nasals in careful speech in English) or having no oral release (like coda nasals in Cantonese)?
In East Asian studies the "no audible release" marker (◌̚) is commonly used for this purpose, but apparently using that marker on non-stop consonants is disputed by some:
Release is only meaningful for a stop. If there is no occlusion, how can it be released?
The chart of the symbols in he IPA is given here: as you can see, there is no diacritic indicating "oral release". In the case of a language like Kaingang with complex oral+nasal contouring (see Wetzels & Nevins, Language 2018 vol 4), superscript oral and nasal letters are positioned appropriately so that one could write an orally-released m as m followed by superscript b. This is not IPA usage, but superscripting release properties is often written this way. However, it would be functionally equivalent to writing [m͜͜b̆], the breve indicating "not a full "b" and the tie indicating "a single segment", which does only use IPA letters and writing conventions.
I assume by "no oral release" you mean no release of the oral occlusion during voicing (or perhaps a release with no compression of the air trapped behind the occlusion). In that case, you can just use the no audible release diacritic. For example, the typical pronunciations of "Cannes" in French and English can be distinguished as in [kan] vs [kʰan̚]. (Or you could mark the released one with a superscript schwa, as in [kanᵊ].)
