In other words : Did America ever anticipate a nuclear strike on its soil when USSR crumbled? I know this might sound like a stupid question , but all USSR had was weapons. A poor man with weapons has nothing to lose. Thats why I ask.
To an extent, yes. A special concern was a potential brain-drain of WMD material and know-how; that nuclear weapons specialists might be grabbed or bought by countries trying to obtain WMDs (or other actors, like terrorist groups). Attempts by USSR scientists to sell materials like plutonium have been documented since the early stages of the 'collapse' of the USSR, and have been a continued problem since. As an example, the Japanese Aum Shirinkyo (architects of the gas attack in Tokyo) are known to have researched procuring WMD technology from the ex-USSR in the mid-90s.
The US and other NATO responses to this threat were varied. One prominent response to this threat was the 'nuclear cities initiative', a joint US-Russian Federation project begun in 1998, in which ex-USSR WMD scientists would have work found for them to prevent 'brain drain' and nuclear black-marketeering. The project was so-named with reference to the 'closed cities' of the ex-USSR, focussed on nuclear weapons, which fell into dilapidation upon the end of the USSR.
Sources and further reading:
R. Lee, April 27, 2001, 'Nuclear Smuggling From The Former Soviet Union: Threats And Responses'
The Stimson Center (global security thinktank), 2007, 'Russia’s Nuclear Cities'