I'm running ghetto tubeless and Ghetto badboy tubeless on my wheels – I've noticed my wheels need truing and spoke tightening.

Can I do this without taking the tyre off or do I have to remove the tyre and then redo the tubeless afterwards?

As long as it's not too bad it's do-able, but better & easier if you take the tyre off.
Why does it need re tensioning though? Is it a cheap build, as a decent build should never need re tensioning?

what is ghetto bad bwoy tubeless, err, blud ??

Was built up about 18months ago and had some fair abuse recently so I'm not surprised the tension is out.

Ghetto = using 20inch tube

Ghetto badboy = using gaffer tape

what is ghetto bad bwoy tubeless, err, blud ??

+1

ah…i am also a badboy…represent.

No matter how much abuse, if built properly they shouldn't loosen, unless you've got a flat spot in the rim,
Might be worth trying a drop on spoke freeze or similar if it causes a problem.