Is the possibility of a nuclear exchange really high or is this to instill fear in the US public?

The U.S. Air Force canceled an intercontinental ballistic missile test in what the branch says is an effort to avoid increasing nuclear tensions with Russia.

The cancellation of the test, revealed Friday, comes several weeks after the Pentagon delayed testing the Minuteman III missile in early March, shortly after Russia placed its nuclear forces on high alert.

https://www.washingtonexaminer.com/policy/defense-national-security/us-military-cancels-missile-test-due-to-nuclear-tensions-with-russia.

h/t Remedial_Rebel