I get the error on the NIST web site [0] as well. I do have the "Proceed to ..." option, though, as you can see in my screenshot [1].

The same thing happens on the Chase Bank URL [2] mentioned in the article. Clicking "Proceed to ..." then redirects me to another URL [3] which throws up the same error. If I click "Proceed to ..." on that URL, I then get an ironic login page [4].

  $ lsb_release -d
  Description:    Ubuntu 16.04.1 LTS

  $ apt show chromium-browser | grep ^Version
  Version: 53.0.2785.143-0ubuntu0.16.04.1.1254

  $ chromium-browser --version
  Chromium 53.0.2785.143 Built on Ubuntu , running on Ubuntu 16.04

Perhaps there's a setting somewhere that you've toggled? Maybe it's HSTS or something similar?

[0]: https://www.nist.gov/

[1]: http://i.imgur.com/QbgBxyB.png

[2]: https://choosemyreward.chase.com/

[3]: https://chaseonline.chase.com/Logon.aspx

[4]: http://i.imgur.com/KFqiwNG.png