Do you have medical journal articles, studies or the like in support of the proposition that Agent Orange is "more likely than not" or "at least as likely as not" associated with pancreatic cancer? I have treating doctors prepared to complete "nexus letters" but they require such information to adequately support their opinions.
No, I don't catalog such things but Google does and you can use Google search to find a broad selection of science to support you. I can give you a bit of a hint and let you know that any doctor who writes such a opinion for your claim or appeal should know how to support their statements with science...that's nothing new to them.
You can locate similar cases that include a diagnosis of pancreatic cancer and learn their outcomes by searching key words here https://www.index.va.gov/search/va/bva.jsp
For what it's worth we don't refer much to nexus letters these days, we talk of IMOs and DBQs. More on that is here https://www.vawatchdog.org/imo-ime-medical-opinions-exams.html