Many times, it's completely unnecessary to compress highly-distorted guitar tracks, since the nature of distortion itself already limits the dynamic range....
Now if you're trying to use a compressor for color, that's a completely different story. The RNC isn't exactly a "coloring" unit - it's a very effective, but transparent, compressor so it may not give you the sound you're looking for in this specific case....
OTOH, try it and if it works, there ya go...!