I have little choice but to put on my seer's hat and read the tea leaves on this one, because it's not readily apparent what this means.
So yes, Stephen Nicholas has taken on a pair of agents, Doug Hendrickson and CJ LaBoy, which sounds like the worst two man boy band of all time. They're also agents with Octagon Sports and represent at least one prominent Falcon, free safety Thomas DeCoud. To my knowledge, they don't have any particular reputation for being ruthless, which is a plus.
Generally, though, football players change agents when they're angling for something their previous representation wasn't able to get them. Nickels is an impending free agent and a quality linebacker, so it's entirely possibly he's hoping to reel in a big contract on the open market. He might also be looking to come back to the Falcons, but on a better deal than he believed he could land with his current representatives. Fishing term.
My hunch all along has been that Nicholas will try to land the best deal he can, and it may not come from Atlanta. I think Nicholas is about as good a fourth linebacker as you can find in the NFL, which makes him valuable to the Falcons considering Sean Weatherspoon struggled with injuries and Mike Peterson is getting up there in years. Linebacker-thirsty teams like the Lions and the Rams could be interested, and the Lions in particular might be willing to drive the price up.
Ultimately, he could very well be back with the Falcons in 2011. This move makes me think we better not take that outcome for granted, though.