iptables-translate -A INPUT -m tcpmss --mss 42
nft 'add rule ip filter INPUT tcp option maxseg size 42 counter'

iptables-translate -A INPUT -m tcpmss ! --mss 42
nft 'add rule ip filter INPUT tcp option maxseg size != 42 counter'

iptables-translate -A INPUT -m tcpmss --mss 42:1024
nft 'add rule ip filter INPUT tcp option maxseg size 42-1024 counter'

iptables-translate -A INPUT -m tcpmss ! --mss 1461:65535
nft 'add rule ip filter INPUT tcp option maxseg size != 1461-65535 counter'