I do understand the allergy concerns, since I suffer from many allergies myself, and you specifically mention nuts - a true peanut allergy is probably the most deadly allergy on the planet.
FWIW the listing of ingredients in your food likely isn't anywhere near as transparent or inclusive as you might think. I don't have time to pull up the data, but a little googling on the subject can be very enlightening (or scary). But they have, thankfully, been labeling foods with peanuts for a while now.
If the industry would step up and be transparent (at least on things the vaping community is concerned about) - I couldn't be happier!! But meanwhile, if I had a peanut allergy, I would research every juice and avoid those that use ANY natural flavorings, or just go unflavored.