They might as well declare they are president of USA as well while they're at it. Maduro's regime was just publicly emasculated. They already had no legitimacy due to a fraudulent election and now they have no physical power either.
Without might makes right (US puppet) or some recognition of legitimacy, any leader is little more than a loudspeaker in a pretty house.
Trump claimed in the press conference that we will be controlling their government via her as a puppet and if they don't do what we say we'll put boots on the ground. And I am not even slightly embellishing. So sure she is the 'president' but only by proxy.
Without might makes right (US puppet) or some recognition of legitimacy, any leader is little more than a loudspeaker in a pretty house.