Comment # 1 on bug 1228829 from Alexandre Vicenzi

Tailscale requires either iptables or nftables. By default, both options should
be installed in Tumbleweed (and possibly Slowroll).

It is not ideal to require these packages by Tailscale because it can be
changed by the user which firewall backend is being used.

Something seems to be off with your system setup. Can you check that either
iptables or nftables is installed and available in $PATH?

Check the docs [1] to change the default firewall backend in Tailscale.

[1]: https://tailscale.com/kb/1294/firewall-mode