After installing the pychess-0.99.1-1.py36.noarch.rpm from the pychess website, I get:
[mgatto@maggie ~]$ pychess
ERROR: Could not import modules.
Please try to run pychess as stated in the INSTALL file
[mgatto@maggie ~]$ which pychess
/usr/local/bin/pychess
[mgatto@maggie ~]$ cat /etc/fedora-release
Fedora release 26 (Twenty Six)
[mgatto@maggie ~]$ ls /usr/local/share/pychess
ARTISTS AUTHORS boards DOCUMENTERS eco.db flags glade LICENSE pieces pychess_book.bin README.md sounds TRANSLATORS
[mgatto@maggie ~]$ ls /usr/local/lib/python3.6/dist-packages/pychess/
Database external gfx ic __init__.py Main.py perspectives Players __pycache__ Savers System Utils Variants widgets
[mgatto@maggie ~]$ echo $PATH
/usr/lib64/qt-3.3/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/home/mgatto/.local/bin:/home/mgatto/bin
[mgatto@maggie ~]$ echo $PYTHONPATH
[mgatto@maggie ~]$ dnf list pychess