Upvote:2
I found the answer on page 267 in: Oshiro, George M. “The End: 1929-1933.” In Nitobe Inazô: Japan’s Bridge Across the Pacific, edited by John F. Howes, 253–78. Boulder: Westview Press, Inc., 1995.
“His last major appearance to a wider audience was an address to the Institute of International Affairs at Pasadena. He gave an address entitled, ‘A Japanese Tribute to Abraham Lincoln.’ For his work with the Institute, Nitobe was honored, on March 1st, 1933, with an Honorary Doctorate of Law — his fourth —from the University of Southern California.”
The source provided by Oshiro is “Letter received from Paul Christopher, University Archivist, University of Southern California, March 19th, 1985.”
USC is not part of the University of California (that is, the UC system), so Nitobe did not receive an honorary doctorate from the University of California.
I have not found anything to support Nitobe having had received an honorary doctorate from Geneva, but perhaps 『新渡戸稲造事典』written by 佐藤全弘 and 藤井茂 and published by Kyobunkwan in 2013 would contain the definitive answer to that.
Upvote:4
Universities (at least in the US) tend to give those out to famous people as favors for lecturing there. As such, having an "honorary" degree doesn't really mean a whole lot. There wouldn't be much incentive for making up a false story about somebody receiving one.
It appears he did a speaking tour of the US in 1911, and did speak at several universities, so that would be a good place to start looking. I found a dissertation someone did on his speeches from that tour specifically, but it doesn't appear to be available online. My google-fu was only strong enough to ascertain that he did at least talk about California some in the talks.
The only reference I could find to Geneva was that he was there in 1920 when the League of Nations was inaugurated, and became an Undersecretary General for 6 years. It wouldn't be at all surprising if he found some time in the intervening 6 years to speak at the University, nor would it be at all odd for them to give him an honorary degree as part of the deal.