Chad Johnson -- I Love Gel Manicures ... They're Not Just for Chicks!

Chad Johnson is putting the "MAN" in manicure -- telling TMZ Sports he hasn't missed a mani-appointment since 1999 ... and he's damn proud of it.

The former NFL superstar showed off his nail job in a photo on Instagram -- and our crack news team immediately noticed that it appeared the guy was sporting a "gel" job on his digits.

We reached out to Chad ... who told us, "I always get gel so my sh*t doesn't chip" ... adding, "That's all I care about on women, so I have to be right."

Chad says he's obsessed with having polished paws -- and says he's been a regular at his local nail salon "every Friday since 1999 ... I've never missed."