I have a child w/peanut allergy. The recommendations above are good ones. I have another one:

How about Halloween mini grave yards? Use the brands that I have identified to be as safe as you can be. (Definitely AVOID Nestle chocolate chips!)

Chocolate pudding in a clear cup - about 1/2 full (Jello brand is peanut-free)
add Oreo cookie crumbs to the top - just a sprinkling is fine (Oreos are peanut-free)
add a Vienna Finger (Keebler) to the top. You can add a little "RIP" on top of the Vienna Finger with a toothpick and melted chocolate (HERSHEY's mini kisses melted)

Some people add gummy worms, but then you have to check the packaging, because MOST gummy products are NOT nut-free. I go without it.

Be sure to have the labels cut out for the teacher/nurse to review in case there is some apprehension - many kids who have nut allergy don't eat other people's home-made items.

Good luck!