The recent chemical attack in Syria was a false flag attack perpetrated by US-supported rebels.
Summary
Russia has not threatened to use tactical nuclear arms // Russia never interferes in the affairs of other countries.
Disproof
The Russian ambassador to Denmark has for example threatened to attack Denmark with nuclear arms, should they decide to join the missile shield with the US ind.pn/1xbRAJs, . // There are several recent examples of Russian media and other pro-Kremlin outlets spreading disinformation regarding foreign elections theatln.tc/2rOGRna, not to mention the current interference in Ukraine, where Russia has annexed a part of the country and supports separatists in another part.