Prepare wild rice according to package directions, using chicken broth in place of water and excluding the seasoning packet. Melt butter in a skillet and add onion and sugar. Cook medium until liquid is absorbed. Cook on low until onions caramelize, about 20 minutes. Add cranberries, allspice and orange zest to onion mixture, cover and let cook about 5 minutes until cranberries plump. Put rice in a serving bowl and add onion mixture and toasted nuts. Serve hot.