• Great introduction
• product docs
• https://wiki.nftables.org/wiki-nftables/index.php/Stateful_objects

nft list tables
nft list table firewalld

nft add chain firewalld output { type filter hook output priority 0 \; }
nft add rule firewalld output ip daddr 8.8.8.8 counter
nft add rule firewalld output tcp dport 80 counter

nft list chain firewalld output 
nft list chain firewalld output -n -a

nft add chain firewalld input { type filter hook input priority 0 \; }
nft add rule firewalld input tcp dport 80 counter
nft add rule firewalld input tcp dport 443 counter