I just ran into the issue that my virtual machines are not beeing natted properly anymore.
It took me some time to fix it so here are the commands in case you run into the same issues.

Edit Iptables NAT and SNAT

sudo iptables -t nat -A POSTROUTING -s 192.168.122.0/24 ! -d 192.168.122.0/24 -p tcp -j MASQUERADE --to-ports 1024-65535
sudo iptables -t nat -A POSTROUTING -s 192.168.122.0/24 ! -d 192.168.122.0/24 -p udp -j MASQUERADE --to-ports 1024-65535
sudo iptables -t nat -A POSTROUTING -s 192.168.122.0/24 ! -d 192.168.122.0/24 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -s 192.168.122.0/24 -o enp2s0 -j SNAT --to-source YOUR-PUBLIC-IP-ADDRESS

Afterwards it should look like this:

 

Now the clients should be able to talk to the outside world again.

Saving your Work

sudo iptables-save > /path/to/config.file

Cheers,
Ori