In 7 as part of the track mixer channel strip was EQ, visualizations, and COMPRESSION.
I can’t find where to add compressor to an existing track that has none.
If I pull up a track that had compression already enabled, it correctly shows up in the channel strip.
Anyone know where to find it in the UI?
mikelester. You are correct. However, you can add the n-Track compressor to the track as you would any other VST effect - but - once added, the compressor will only partially display in Track EQ window as it did with V7.
Replace above “will only partially display” with “the tool bar, familiar in V7 Track Compressor partially displays in the upper background of the EQ window”, and, it’s looking like the FX button in the Track EQ Prop’s box is malfunctioning, as in, it does nothing. (anyone else)?
Ah! mikelester. Try this - open the Track EQ from the EQ button on the track strip > click on the FX button in the EQ window and choose to “add effect” from the dropdown and choose n-Track Compressor. Hey presto - just like 7 
(the issue I describe further up seems to occur when the compressor is added to the track strip rather than the Track EQ Prop’s window - in this case, the compressor doesn’t appear)
Ah! mikelester. Try this - open the Track EQ from the EQ button on the track strip > click on the FX button in the EQ window and choose to "add effect" from the dropdown and choose n-Track Compressor. Hey presto - just like 7 :-)
(the issue I describe further up seems to occur when the compressor is added to the track strip rather than the Track EQ Prop's window - in this case, the compressor doesn't appear)
You should consider putting this in the User Guide as I had the same issue. The guide told me it would open when I opened the EQ; however, the compressor plugin wasn't there. I had to read through this post to figure it out.
You can just simply update it to say "If the compressor plugin is not present, open the Track EQ from the EQ button on the track strip > click on the FX button in the EQ window and choose to "add effect" from the dropdown and choose n-Track Compressor."
That would have been a huge help and avoided me searching forums. Thankfully the answer was in here.