Lay out several strips of waxed paper or parchment on a countertop for cooling the popcorn after mixing in the syrup/carmel. Butter a large enough bowl to hold the popcorn, and nuts, and still have enough room to mix things together.
Pop the popcorn, remove any unpopped kernels and place in the buttered bowl with the pecans. Set aside until needed.
Combine remaining ingredients, except candycorn, in a medium saucepan and heat slowly to a boil, stirring until the sugars melt. Cook syrup to hard crack stage (290° to 295° F)
Remove syrup from the stove and pour in a fine stream over the popcorn mix, stirring carefully until well coated. (It helps if you have an assistant here to stir as you pour, but not absolutely necessary)
When the mixture is well coated but has cooled slightly, add the candycorn over all and stir quickly to stick it into the carmel coating. It is important that the carmel not be completely cooled when you add the candycorn, but if it is too hot, the candycorn will melt too much.
Spread the mixture out on the waxed paper or parchment and separate it into bite sized pieces with two forks. Allow to cool completely. Put it into your favorite Halloween bowl and enjoy!