A new kernel version arrived for F23, 4.5.6-200, and Nvidia still works fine without me doing anything special.
Below is my updated procedure in case someone needs it. It should work for new-ish Nvidia cards (mine is 3 years old).
I installed the dkms package because someone recommended it in this thread, though I am not sure it is needed. Also I installed a few packages recommended in the RPM Fusion website such as vdpauinfo though again I am not sure they are needed. In any case, these packages are not causing me any harm. There is no need to uninstall the Nouveau driver.
I am left wondering why we even need such a procedure. For example, why doesn't installing akmod-nvidia and xorg-x11-drv-nvidia pull all the other needed packages and run dracut? I know nothing about packaging so maybe there is a good reason for that!
# Run the commands below as root or with sudo
# Make sure we are up to date
# Install a bunch of packages
# This is an explicit list and it could be made shorter as some packages depend on others, the long list is just for clarity
dnf install akmod-nvidia xorg-x11-drv-nvidia xorg-x11-drv-nvidia-devel xorg-x11-drv-nvidia-libs gcc kernel-devel vdpauinfo libva-vdpau-driver libva-utils dkms kernel-headers xorg-x11-drv-nvidia-libs.i686
# Backup old initramfs nouveau image.
# There are two alternatives to this: delete old image or use the parameter "--force" in dracut below
mv /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r)-nouveau.img
# Create new initramfs image
# There is no need to use "--omit-drivers nouveau" because the nouveau driver is automatically blacklisted as a result of installing xorg-x11-drv-nvidia
dracut /boot/initramfs-$(uname -r).img $(uname -r)
# After reboot, this command should not output anything if the Nvidia driver is being used:
lsmod |grep nouveau