Rich went on to comment about Kaepernick's widely publicized "pig socks," which the former NFL quarterback wore while kneeling on the field during the National Anthem. The black socks featured a pig dressed up as a police officer, an obvious jab at law enforcement.
"Hey @Nike, if you're gonna make the shoes, make the PIG SOCKS to match. Right? Cmon, people will LOVE that," Rich tweeted.
Rich's musical counterpart, Big Kenny, hadn't commented on the Nike ad campaign at press time.
As previously reported, the new black-and-white ad features Kaepernick's looking at the camera, with the printed words: "Believe in something, even if it means sacrificing everything. #JustDoIt."
Kaepernick has been a Nike athlete since 2011, but the Super Bowl QB has not played on a team since 2016.
The athlete created a national firestorm when he began kneeling during the National Anthem in an effort to protest African-American inequality in America.
Since then, a number of players on all teams have kneeled or raised a fist during the anthem for the same protest.
See Rich's tweetstorm below.