agree, Spanish are oppressive on 1v1 Nomad.
And I personally would just start with taking away the building speed on the 1st TC.
If Sicilians dont get that speed, I dont even understand why Spanish should have that.
And from there on I would wait and see how it feels.Spanish can already get problems when you take away their fish.
They can really struggle to keep up the Conq production then.
If they also lose their ~2 vill advantage, that only gets worse and maybe forces them to fight for some water, which would then make their castle age timings worse.