According to Herman Wouk's fictionalized account of the war Nimitz explained this by saying his memoirs could be summed up in two words: "We won."
That has the ring of non-fiction.
I think that, on the one hand, Nimitz recognized that his contribution to winning the Pacific War was extremely important, but at the same time, the “big picture” was SO big that even the greatest individual leader was still a speck, like a super-carrier in the Pacific!
We went to the Museum of the Pacific War years ago, when we still lived in Texas. I’d love to visit it again.