Latin America doesn't really work. For a successful insurgency, you need a base area the counter insurgent cannot reach and a secure supply line. Nobody in South America is going to tell the US to go screw itself, and no major Latin American country will let its ports be used to ship Communist bloc arms to shoot at the US. Of the Latin American countries Cuba is literally the worst as it is an island, the US can search every ship that comes in and cut off supplies
with Vietnam, supplies could just go in by train or freighter to the North, and the US could not launch major incursions easily. South America is afraid enough of the US they won't willingly let their borders be used as a sanctuary or act as an arms pipeline. Absent that yes you can get an insurgency, but it won't be a Vietnam level insurgency. And even a Vietnam level insurgency is not enough to inflict a Vietnam level defeat on the US, you need an equivalent of the NVA Regulars moving down into the South
For a Vietnam level defeat, probably only Vietnam, elsewhere in South East Asia, propping up a Nationalist China that holds the South, or someplace in Africa like Congo