Big & Rich Singer Blasts Nike for Signing Colin Kaepernick

John Rich -- one half of the country band Big & Rich -- is FURIOUS at Nike for the mega deal it made with Colin Kaepernick ... and says his sound guy is already planning on burning his Nike gear.

As we previously reported ... Nike signed Colin as part of its "Just Do It" 30th anniversary campaign -- a deal that includes a custom shoe, custom apparel and other Kaepernick-centric merchandise.

John Rich feels the deal is an insult to law enforcement -- and points to the incident where Kaepernick wore a pair of socks featuring a pig dressed up in a police uniform. "Hey @Nike, if you're gonna make the shoes, make the PIG SOCKS to match. Right? Cmon, people will LOVE that," Rich tweeted. He also wrote, the deal "makes me sick."

ICYMI ... Colin wore those socks during training camp in 2016 when he was the 49ers QB. He later clarified, "I wore these socks, in the past, because the rogue cops that are allowed to hold positions in police departments, not only put the community in danger, but also put the cops that have the right intentions in danger by creating an environment of tension and mistrust."

Kaep added, "I have two uncles and friends who are police officers and work to protect and serve ALL people. So before these socks, which were worn before I took my public stance, are used to distract from the real issues, I wanted to address this immediately."

In addition, Rich says the band's sound man "just cut the Nike swoosh off his socks. Former marine. Get ready @Nike multiply that by the millions."

On the other side, Colin is getting TONS of support from celebrities like Serena Williams, who posted "Love this." Other stars like T.I., Ava DuVernay and Swizz Beatz have expressed their support for Nike and Colin as well.

One thing's for sure ... this story ain't going away any time soon.