word for word: haciendo nada
If you mean: (I'm) doing nothing - No hago nada
"Nothing" in Spanish is "nada".
"Nothing" is "nada" in Spanish.
¿Cómo estàs ustedes? is how you say "how are you doing everyone?" in spanish.
you say no tengo nada
Hacer
It does seem to be an axymoron of sorts. If it's nothing, how can you be 'doing' it? I say it is OK to say it. Everyone knows what the phrase means, and so it is useful. If you are uncomfortable about the illogic of it, say 'nothing in particular', or 'nothing special'.
Doing good = haciendo bueno but this sounds terrible in Spanish. Generally speaking you should say "doing well" which is haciendo bien.
No fue nada.
No mucho
No es nada.
¿Qué haces?
Que hace?