As to the US and nation building, well, we don't have a very good history there, at least not recently. I'd just as soon the US doesn't get involved in such in Venezuela. The offer to those remain seems to be a "work with us or get out of the way," meaning we don't particularly care how they do things so long as they aren't a nuisance to the US. That might not be what humanitarians want to hear, but given our track record, might be for the best there, too.
As to the oil, I think Chevron is still there, but if I had an oil company, I wouldn't be in a rush of going back to Venezuela.