There are at least two other products on the market and they are easy to use.
Just quit buying epi pens. Tell your doctor/school you won't be using it and deal with it.
If I send my child to school with an "off-brand" epipen with a doctor's note and direct the school to use this instead, they have to observe it -- a nurse is in no way capable of making a drug administration decision without the consult of a licensed medical doctor.
Nurse isn't a protected title, so it's possible a school nurse has minimal qualification and no professional registration.
I dunno if it's similar in the US.
It honestly is a completely irrational fear.