TIA for your help thus far.   Following your advice, here is a diag tool I ran on my HP Ultrium LTO-4 that indicates all is working well on it and verifies it is /dev/nst0.   I have checked my logs and the last error I've seen was a few days ago, nothing produced by the diags done recently.

Main > Drive Information > Device Performance Tool > Viewer >
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- Device Performance Test Started on Drive (Ultrium 4-SCSI) (0.0.0[0-/dev/sg0])
  - Opening Tape Drive 0.0.0[0-/dev/sg0]
  - Successfully opened the Tape Drive /dev/nst0
  - 2147 MB written in 28.6348 seconds at 74.9955 MB/s