Iran nuclear sites hit - seemingly little to no radiation being reported

None of these sites were reactors. Fordow and Natanz are (were) enrichment facilities. They deal mostly with UF6 (Uranium Hexafluoride) which is a gas above 56℃. The gas is run through centrifuges to enrich the uranium. If bombed the UF6 could vaporize and react with moisture to produce HF gas (hydrogen fluoride) and uranyl compounds that would be localized to the area and not drift off much in the wind. The Esfahan facility is a Uranium production facility - they take ore and process it into yellowcake then UF4 (Uranium Tetrafluoride) a green solid, then to UF6 which is then sent to the Fordow and Natanz facilities for enrichment. Like Fordow and Natanz, if Esfahan was blown up the fallout would be localized and not like traditional nuclear fallout. My understanding is the regular fallout we all know is only produced by a reactor or spent fuel exploding, or a nuclear bomb.

I suspect there will be some fallout, but not in the traditional sense. And this will be localized to the areas. Fordow and Natanz's centrifuges were underground, whereas Esfahan was mostly overground.