I have seen many threads asking what the easiest Nepenthes are, so I'll make it easier for anyone who wants to know.
The easiest species are Nepenthes:
reinwardtiana (i have heard stories that this can do well as a highland too)
alata (lowland forms)
ventricosa (though highland, it can grow here well)
khasiana (highland, but tolerant)
I hope i've helped you all!