Prepare one regular-sized bag of microwave popcorn according to the directions on the package.
Empty the popped corn onto a large cookie sheet.
In your microwave, heat 1 to 2 ounces of white chocolate morsels.
Drizzle the white chocolate over the popcorn, sprinkle with rainbow nonpareils, and place in the freezer for just a few minutes, until the chocolate sets.
Break apart, and enjoy!