Let me try to explain how styling works in Ninjaboard.
Chameleon is not a specific style that gives your forums a specific look.
Chameleon is a clever solution that makes Ninjaboard perfectly blend in with your Joomla! template.
So in other words Chameleon makes use of the module styling that your active template provides.
If your template doesn't have much styling to offer then Chameleon won't or can't make that much better.
But if you have an awesome template (for instance Rockettheme, Yootheme) then Chameleon has the power to make use of the multiple styling options that such a template can provide.
So, if you want to take full advantage of Chameleon and make Ninjaboard look really awesome, you have to install different templates and see what is the best fit for your needs.
For instance, you can play around with the standard templates that comes with the standard Joomla! installation.
There are also a lot of free templates available on the internet (try Google) but for more top templates you have to pay. Those templates where you have to pay for are merely the ones that makes Chameleon benefits the most. However, some of them are also downloadable for free.
Take a look here http://www.rockettheme.com/joomla-templates for a professional top template (scroll all the way down).
I hope I've given you a step in the right direction.