Wheel Lug Cover
 

2017 Comaro 1le with 20” chrome wheels. How do you remove the black star lug cover?

If it's this piece below, I think it simply pops off, screws or rivets can't be used in this spot.

Correct - simply pull off that ugly plastic thing and replace it with a traditional sixth gen center cap of your choosing!

Some of them are really tightly fit on there, and short of taking the wheel off to punch them out... I found two ways to get them off easy.

First, if they don't have a raised surface, a suction cup from something like a phone mount will usually pull them off.
Second, if I'm going to toss them, I'll just drill a small hole in it, and use a pry / pick tool to just pop them off.

Those are useful suggestions for removing the small round center caps, but those techniques shouldn't be necessary with this one. Unlike a typical center cap or hubcap, you can get your fingers behind the "points" of the "star" and just pull it off. Super easy!

Star Cap Removal
 

The method that works consistently for me is grab the outside of two opposite (not adjacent) "legs" and rock back and forth to loosen the center attachment.