Iran was enriching nuclear material, which it has been using for civilian nuclear power generation. This is an important distinction. The American regime is "flooding the zone" with bullshit, so that when we hear "nuclear," your mind sort of auto-completes the phrase with "weapons." But Iran has (had?) a nuclear enrichment program that was verified by the IAEA to be used for things like radiation therapy to treat cancer, and power generation.
The idea that it has to be "weapons" is implanted in your mind with propaganda techniques, like Goebbels' big lie.