set firewall name FOO rule 10 action 'accept'
set firewall name FOO rule 10 source address '192.0.2.2'
set interfaces ethernet eth1 vif 5 firewall local name 'FOO'

vyos@r14# sudo nft list table ip filter
table ip filter {

	chain VYOS_FW_LOCAL {
		type filter hook input priority filter; policy accept;
		iifname "eth1.5" counter packets 0 bytes 0 jump NAME_FOO
		jump VYOS_POST_FW
	}

...

	chain NAME_FOO {
		ip saddr 192.0.2.2 counter packets 0 bytes 0 return comment "FOO-10"
		counter packets 0 bytes 0 return comment "FOO default-action accept"
	}
}

[edit]
vyos@r1# sudo nft list table ip filter
table ip filter {
	chain INPUT {
		type filter hook input priority filter; policy accept;
		counter packets 13644 bytes 1993144 jump VYATTA_PRE_FW_IN_HOOK
		counter packets 269 bytes 33536 jump VYATTA_FW_LOCAL_HOOK
		counter packets 13644 bytes 1993144 jump VYATTA_POST_FW_IN_HOOK
	}

...

	chain VYATTA_FW_LOCAL_HOOK {
		iifname "eth1.5" counter packets 0 bytes 0 jump FOO
	}

	chain FOO {
		ip saddr 192.0.2.2 counter packets 0 bytes 0 return comment "FOO-10"
		counter packets 0 bytes 0 drop comment "FOO-1000000 default-action drop"
	}
}