I noticed you seem to have an addon that gives you your character panel at the top of the screen as well. Might I suggest something for you to do to minimise the addons you need.
1. Disable all addons except nUI.
2. Play around a bit in PVE and see what is missing.
3. Enable the addons that gave you that functionality and repeat step 2.
4. Play around a bit in PvP/Arena if you do that stuff and see what is missing.
5. Enable the addons that gave you that functionality etc.
Finally enable the raid required addons that are still needed and you should be ready to go.
Any addons in your addon screen that you have yet to enable are probably incorporated into the nUI addon and thus no longer needed. If, however there is functionality in said addon that isn't in nUI feel free to discuss it in the forums as sometimes functionality like that is added into nUI for completeness.
Welcome to the nUI family and I hope you have fun playing with it
