The rest of the world isn’t going to say “whelp, I guess it’s time to kick off the extinction of our species” and do a full set of city strikes over a tactical nuke being used. That would be absurd.
You say that nobody will went crazy when a tactic nuke will be used against RF army. Right?
Can you draw the line, please? When this war between two nuclear states will be nuclear, if even use of tactical nuke is not enough for you?
No idea what salami tactics means.
A tactical nuke used against Kharkiv would certainly lead to either a Ukrainian dirty bomb strike against Moscow and or a NATO intervention. Why would Russia stop at one nuke when fighting NATO? For each tactical nuke against NATO you would expect at least one in return, or worse a megaton +x% for megaton exchange.
This spirals into full nuclear war very quickly once one side believes that they are going to lose without strategic weapons, or one side believes they have been or will be the victim of a strategic attack.
Speaking of, how long until the country with all of the old Soviet weapons facilities decides to re-enter the nuclear club?
[1]Budapest Memorandum was not fulfilled, so Ukraine regain their status of nuclear state.
AFAICT, the person you were responding to wasn’t talking about a nuke being used against NATO forces.
If "tactical" nukes are a thing why hasn't anyone used them since 1945? Seems like they could have been handy in Syria or Afghanistan. There's no shortage of examples of nuclear powers going to war with non-nuclear non-NATO countries in the last 77 years. None of them involved nukes in any capacity.