From the gospel of Wikipedia:
Jimmy Nolen (April 3, 1934 – December 18, 1983) was an American guitarist known for his distinctive "chicken scratch" lead guitar playing in James Brown's bands.
Nolen developed a style of picking known as "chicken scratch," in which the guitar strings are pressed lightly against the fingerboard and then quickly released just enough to get a muted “scratching” sound that is produced by rapid rhythmic strumming of the opposite hand near the bridge. This new guitar style was affected not only by Nolen’s choice of two and three note chord voicings of augmented 7th and 9th chords, but also by his strumming straight 16th note patterns, as in James Brown’s "Papa's Got a Brand New Bag." Nolen’s choices of guitars and amplifiers also affected the sound for which he would be nicknamed. In his first recordings with James Brown, Nolen used a Gibson ES-175 and an ES-5 switchmaster, both hollow body jazz guitars equipped with single coil P-90s. He also relied on a Gibson Les Paul Recording model with single coil pickups, an Acoustic Black Widow, and a Fresher Straighter, which were also single coil instruments. The single coil pickups on these guitars produced a thin "chanky" sound; Nolen ran these guitars through a Fender Twin Reverb with the treble set at 8 out of 10. The result of these factors was a rhythm guitar sound that seemed to float somewhere between the low-end thump of the electric bass and the cutting tone of the snare and hi-hats, with a rhythmically melodic feel that fell deep in the pocket. A good example of such tone would be in James Brown’s "I Got You (I Feel Good)" and "I’ve Got The Feeling."
In the video below I'm 99% positive that is Jimmy in the back with the tobacco Les Paul on the Mike Douglas show in 1970. But whoever it is it illustrates the style. Watch closely starting at 40 seconds into the clip and you can see his right hand technique - downstrokes and then an upstroke for the augmented 9th on the 3rd beat of each measure.