I would use equal parts of orchid bark, perlite, and LFS or sphagnum peat moss, maybe both, but thats what I would do, sometimes I change my nepenthes mixes to find the right consistency for the area I'm growing in and what not.
Today I just re-potted some plants and made up a mix on the spot of 2 parts sphagnum peat, 2 parts perlite, 1 part pumice, and 1 part vermiculite. It's really all up to you and how you want to grow, but I would probably wait for someone elses response.
Good luck with your plant.