Do you use regular table salt when making a nasal irrigation?

You can. Some people like to use non-iodized salt but most people seem fine with regular table salt.

Sea salt can irritate the nose further due to the extra minerals, algae, and other particles.

There is a pharmaceutical grade salt that’s non-iodized but it's costly and usually requires special ordering whereas you can get pickling salt in most grocery stores and it's cheaper and just as good.

I've included a link to an RN's reply to a similar question as well as a link to a nice set of instructions for making your own solution.

Good Luck!