I tried using --target it gives different error every time.
lxdtest@lxdtest8:~$ sudo lxc network create lxdbr0 ipv4.address=10.8.8.1/24 ipv4.nat=true ipv6.address=fd68:3604:ad86:9::8/64 ipv6.nat=true --target lxdtest8
Error: Invalid config key 'ipv6.nat'
lxdtest@lxdtest8:~$ sudo lxc network create lxdbr0 ipv4.address=10.8.8.1/24 ipv4.nat=true ipv6.address=fd68:3604:ad86:9::8/64 ipv6.nat=true --target lxdtest8
Error: Invalid config key 'ipv4.nat'
lxdtest@lxdtest8:~$ sudo lxc network create lxdbr0 ipv4.address=10.8.8.1/24 ipv4.nat=true ipv6.address=fd68:3604:ad86:9::8/64 ipv6.nat=true --target lxdtest8
Error: Invalid config key 'ipv4.address'
lxdtest@lxdtest8:~$ sudo lxc network create lxdbr0 ipv4.address=10.8.8.1/24 ipv4.nat=true ipv6.address=fd68:3604:ad86:9::8/64 ipv6.nat=true --target lxdtest8
Error: Invalid config key 'ipv4.address'
lxdtest@lxdtest8:~$ sudo lxc network create lxdbr0 ipv4.address=10.8.8.1/24 ipv4.nat=true ipv6.address=fd68:3604:ad86:9::8/64 ipv6.nat=true --target lxdtest8
Error: Invalid config key 'ipv4.address'
lxdtest@lxdtest8:~$ sudo lxc network create lxdbr0 ipv4.address=10.8.8.1/24 ipv4.nat=true ipv6.address=fd68:3604:ad86:9::8/64 ipv6.nat=true --target lxdtest8
Error: Invalid config key 'ipv6.address'
lxdtest@lxdtest8:~$ sudo lxc network create lxdbr0 ipv4.address=10.8.8.1/24 ipv4.nat=true ipv6.address=fd68:3604:ad86:9::8/64 ipv6.nat=true --target lxdtest8
Error: Invalid config key 'ipv4.nat'