Is it possible to activate/navigate Nexus via the keyboard? I played around with it and I couldn't find any settings for it, but reviews for this program list keyboard navigation as a feature. Am I just mis-informed or is there something I'm missing?

Not sure what your expectations for keyboard navigation under Nexus are.

If you mean launching applications through the keyboard, just associate a hotkey to each of the shortcuts in the dock. You can do this by right clicking a shortcut, selecting Dock Entry Properties, then setting the Hotkey field to a key combination of your choice.