I have a nozzle on the side of a large cylindrical tank (which is actually a studding pad - so using the term "nozzle" to describe it may be incorrect) for which I have loads as calculated by a CAESAR analysis. I need to verify that these loads are acceptable either by using WRC or whatever is applicable. Has anyone run into this before? Is WRC even appropriate to use? Any guidance would be greatly appreciated.

I understand your subject is a studding pad, i.e a connection which provides a bearing surface for various devices- it may be a mixer, for example.

About WRC107, the connection is assumed to be a rectangular loading surface (in fact the model has no nozzle attached to shell and no hole cut in shell) for circumferential and longitudinal moment loads. For this fact I think you can consider WRC107 for your application, remaining in the same degree of approximation as when consider it for a real nozzle connection.
However, IMO, for your case it remains to evaluate which is the actual load transfer surface and on which basis would you determine the proper size of the repad- i.e the distance from perimeter of the load surface to the edges; I think you can try to adapt the ASME requirements, adding some margin.
I speculate here because when working with a nozzle you have rules for dimensioning the pad versus the "hole" and there are some FEA studies regarding the localization of the General Membrane stress (PM), the Primary stress (PM + PL + PB) and (PL + PB + Q), indirectly confirming the adequacy of the repad size required by ASME.

Of course a specialized FEA analysis would be a better solution of your problem.

Thanks Mariog!