Cream together the butter and sugars until fluffy. Scrape down the sides of your bowl as necessary.
Beat in the eggs, one at a time, then the extract.
Fold in the flour and oats.
Fold in the chocolate chips and nuts.
Spread the batter into the pie shell and bake for about 45 -50 minutes until lightly browned and set. A toothpick inserted in the center will come dryish (meaning no uncooked dough clinging to it, but it will be moist and there will be melted chocolate) Better to under cook than to over cook this one.