League of Legends (LoL) Question: Guardian Nami?

Guardian is not a bad idea. However it is not very good idea either. According to u.gg and some guides around here, you will have most success by running Summon Aery, those are generally much more effective almost every time. It has a lot shorter cooldown, allows Nami to poke more, is easier to proc and is more reliable as well. Feel free to keep using Guardian though, If it is making your games more fun, I personally prefer Prototype: Omnistone on Nami but truth is, it is quite trol. Hope I cleared your question, have a good day!

It's pretty good, just more defensive. Probably a good idea to run it against all-in / catch lanes where you're likely to get bursted. In general, Aery is better since it helps you trade & has a much lower cooldown.