Restrictions on building nuclear bombs are defined in the voluntary Non-Proliferation Treaty, and is not applicaple to non-parties (India, Israel, Pakistan, South Sudan).
Every foreign intervention done by US / NATO through-out has backfired, and worsened the problem it tried to solve.
Case in point: CIA covertly arms Afghan Mujahideen fighters to wage war against the Soviet Union by proxy in the 80s - 90s. But David Hasselhoff did a song, so the Soviet Union fell apart, and Afghan fighters pivoted to civil warfare as Taliban.
Sadam Hussein was a rogue US puppet-dictatorship gone wrong. But 'freeing' Iraq from Hussein entailed destroying their entire civilisation. Just the mayhem caused a million deaths through starvation, sectorial violence, collapsed healthcare, terrorists roaming the streets, etc.
We also destroyed Korea, Cambodia, Vietnam, Libya, Yemen, Guatemala, Chile, etc. (At least for a while)