Bernie Nicholls is a guy who gets knocked for not necessarily being a guy you win with, and for being a guy that's widely seen as doing his best work as a supporting actor. It's not necessarily completely accurate, or fair, but it's the challenge he faces.
During his playing days, he was seen as a guy who could give a very good amount of offense, especially on weaker teams where his production was one of the few highlights. But there was a perception that if you wanted to have success with Nicholls on your team, you either had to put a star in front of him or a star next to him. Beyond that, there was the perception that Nicholls was one of those guys who did his best work on bad teams. In other words, when teams would take the next step, it was usually by implementing a system or utilizing players who fit that system better than Nichols could. That perception was born from his departures from LA, NY, and even (to an extent) NJ. In other words, he was the guy you either traded for the pieces that took you to the next level, or the guy you rolled out there right before your team hit the next level.
In other words, if someone is building a championship team, a GM wouldn't go out and say "get me a Bernie Nicholls" or "Bernie Nicholls type" to build around.