Process pecans and wafers separately; combine in food processor with sugar.
Slowly pour in liqueur until mixture forms a ball. You might not need the whole amount. (If mixture gets too wet, put it in the refrigerator, uncovered, overnight to dry out some.)
Shape into small balls; roll in additional finely chopped pecans.
Store in tightly sealed container.
Notes: You can substitute Oreos for the wafers, and use only 1 1/3 cup confectioners sugar.