Kayleigh's answer is the most logical in relation to your sentence.

Where do they come up with these? I just laugh and think it can't be good.

I haven't heard this before but from the context I would say "isn't useless". The phrase is very informal (maybe even crude) and depending on interpretation should be considered carefully before use! It is a metaphorical phrase - normally you suck something to obtain moisture/liquid from it - for example, an ice lolly. If you suck a nut (like a walnut) you cannot get anything from it - there isn't much moisture there - it is a useless action. Alternatively though "nuts" is an informal way of saying a man's testicles...