The problem with Nicey is that it’s a child theme which uses bp-sn-parent theme and it doesn’t exist in BP 1.2.4.1 anymore.
“The screen shot you see was for version 1.x in which buddypress bp-sn-parent theme had vertical menu and so had bp-nicey(It is a child theme)
In current version of buddypress the parent theme does not offer a vertical menu and so it is not in bp-nicey.
Please take a look at the backward compatibility plugin and bp-sn-parent theme for the vertical menu.” http://buddydev.com/buddypress/bp-nicey-a-simple-and-clean-child-theme-for-buddypress/comment-page-1/#comment-1695
Backward compatibility plugin (https://wordpress.org/extend/plugins/buddypress-backwards-compatibility/) disables link functionality from main menu in my installation, so it’s not an option. Not compatible with WP3 just yet? Re-factoring and css creation doesn’t sound like an easy solution either