Correct connector?

I removed the AC unit from my friend’s RV. That was the right move.

RV place absolutely butchered the install. It’s horrible. The roof that the AC sat on originally had a 1" lip to the interior. This kept water out in most situations even if the bottom wasn’t sealed. They sawed away that lip and stuffed some packing foam into the resulting space. Arrows shows the remnant of the lip at the edges.

They cut the power cord so they could route it through the wall. Reconnected with wire nuts and electrical tape.

I’m sure wire nuts on stranded wire in the high vibration RV environment is not correct. Anyone know the correct connectors? Or the correct Google search words? I did not have any luck.