ooops, there is no easy asnwer to this, and it confuses a lot of people reading Div. 2 when loads are classified as primanry and secondary, and all kinds of combinations which are not taught in school. It is somehow against the traditional concept of "Statics".
Since shell and nozzle junction is not really regid, it will absord loads or redistribute, relax, or self-limiting, self-constraint, unrelenting, you name it. The load is not actially transfer to the support due to the effect, especailly thermal load which is considered as secondary. Sustained load, pressure thrust or so called dead load, which may be the load you want to take a serious look.
For a vessel with skirt support, we hardly consider to transfer any nozzle load except the overhead piping and other attachments,which dead load can create eccentric moment you have to consider.
Many loads can cancel each other as TGS4 says.
I have several cases which I do consider to transfer nozzle loads and pressure thrust given by Piping group, especailly the nozzle is not small and come with big rigid re-pad.
In your case since it is leg support, I assume it is a small vessel, and nozzle load can have an impact on leg to pull,push or twist it if the nozzle is not small compared to the vessel. If I were you, I will take all 6 forces transfered to leg, purly based on conventional "statics", forgert about primany/secondary. Structual steel won't cost that much. Be conservative and you can sleep well, and no one can say you are wrong.