I'm answering my own request. I think I just found what I was looking for in an old church cookbook. We called them Congo Bars; looks like others called them Fudge Bars. They taste pretty close and are very good.

Fudge Bars

1/2 c. shortening
1 c. brown sugar
1/2 t. vanilla
1 egg
3/4 c. flour
1/2 t. soda
1/2 t. salt
2 c. quick oatmeal

Combine 1st 3 ingredients together well, add beaten egg, dry ingredients and oatmeal. Press in 9x13 pan, reserving 1 cup.

6 oz. chocolate chips
1 can sweetened condensed milk
1 t. butter
1/4 t. salt

Cook over low heat until chips are melted. Remove from heat and add 1 t. vanilla and 1/2 c. chopped nuts. Pour over crust and spread reserved crumbs on filling. Bake at 350 for about 25 minutes.