i would say that the united states is not attempting a coup in venezuela because, to me a coup strongly implies an illegal seizure of powe,r and afaik the national assembly's effort to remove maduro is in accordance with the venezuela constitution.
that notwithstanding, while it is possible that the united states might materially aid the effort to remove maduro in the future, i have no evidence that they have already done so, so even if it were a (thus far fruitless) coup, i have no reason to think that it was undertaken at the behest of the us.