Try this instead:
rdate -p time-b.nist.gov
rdate -s time-b.nist.gov
rdate -v time-b.nist.gov
The first one should show the difference (but not adjusting)
The second one should adjust
The third one should show that it's 0 seconds off.

I used time-b.nist.gov instead of time.nist.gov (time-b doesn't use ntp so I left out -n then) because time.nist.gov gave me that message you printed, but also didn't give enough replies to allow setting the time.