All else being equal, a one chip camcorder will perform better in low light than a three chip camcorder. Because the three-chip system has to split the light into three streams, each containing one-third of the light energy that entered the lens. Therefore each of the three chips have to amplify it to digitize it, causing the typical problems of amplification - distortion.
But, of course, all things are not equal so there are three-chip camcorders that outperform one-chip camcorders in low light. And, of course, three-chips gives better color and motion.
Regards
Peter