Hey Platy,
You can run LaunchBar actions via AppleScript:
tell application "LaunchBar"
perform action "Chrome Tabs"
end tell
So you can assign whichever action you want to a script like this one above and run it from a Keyboard Maestro Execute an AppleScript action with a specific keyboard shortcut.
You may also want to see my macro: Safari » Switch Tabs-Windows Using Pick-List.
I have one of these available for Google Chrome too.
-Chris