Nginx on Fedora 26: could not build optimal types_hash error message
On Fedora 25, I had this problem as well. types_hash_max_size was set to 2048 (nginx documentation indicate it defaults to 1024). I simply increased it to 4096 and nginx was happy (checked with nginx -t).
FWIW, in my configuration there is no setting related to the hash bucket size. It's just the default.