iptables -A FORWARD -i wg0 -o YOUR_INTERFACE -s 10.200.200.0/24 -j ACCEPT
iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -t nat -A POSTROUTING -o YOUR_INTERFACE -s 10.200.200.0/24 -j MASQUERADE
see vpn.netdev
and vpn.network
.