Hi
Yes, some of the nutrients are lost in the cooking process so it is reccommended that you don't cook more than one pack a day. I had one pack made into crisps every day for 4 months and I was still thriving so I can personally vouch that whatever nutrients are lost, it's not enough to do any damage!!
Making crisps can be a bit tricky at first, there's a definite knack to it. First few attempts of mine I ended up eating soggy stogey soup mix and paper. Try to get a teflon baking sheet to use in the microwave as non stick grease proof paper/ baking parchment etc do not work!
Enjoy!