Coming up with appropriate Halloween treats is a tricky question for parents these days. Once, I would have suggested handing out fresh fruit as a nutritious treat, but conscientious parents and safety experts warn kids not to accept fruit or unwrapped goodies of any sort.
As for most of the big-name, individually wrapped candies - they are a nutritional nightmare, and I suggest steering clear. Chocolate can be good if it's pure. That means no fats other than cocoa butter - make sure that first ingredient is chocolate, not sugar. If it isn't chocolate, it's probably some sugary, artificially flavored and colored horror, and should not be given out to kids - or adults, for that matter.
Some general attributes can make your sweets slightly less pernicious than many others. Any chocolate combination with nuts or peanut butter will rank highest in calories and fats, while any combination with mint or marshmallows will rank lowest. Caramels are also relatively low in fat, but they make sugar stick to teeth; in other words, they're cavity-makers. The same goes for other sticky stuff like licorice, taffy, lollipops and so many of the artificially flavored fruit candies. Little boxes of raisins (organic only) are always an option. There was a time when these would garner you a pelting of eggs or a toilet-papered mailbox, but lately, as obesity and type 2 diabetes have become more common in children, I find more parents and kids are open to alternatives like this. Good thing, too - according to recent estimates, as many as one in three adults may have diabetes in 2050, so today's children definitely need a course correction.
Other alternatives: Look in a health food store for puffed rice squares, granola bars or other treats. Or hand out snack-size bags of pretzels (read labels) or popcorn (the air-popped type if you can find it) or even little, inexpensive toys. You could even take all the money you would normally spend on Halloween candy, convert it into pennies, nickels and dimes, put it in a big bowl and let each kid grab a handful.