Over a double boiler on low heat, combine chocolate chips, heavy cream, and butter. Stir until chips are melted and mixture is smooth. Remove from heat, stir in coffee liqueur. Let cool for 10 minutes.
Spread 1/2 C sauce on bottom and up the sides of the chocolate cookie crust, letting it pool in the bottom. Shake gently to level out. Freeze for 15 minutes.
In a small bowl, combine cookies and cream ice cream and 1 Tbsp coffee liqueur. Pour over fudge sauce layer in pie pan. Freeze 2 1/2-3 hours.
Once the first layer is mostly frozen, combine remaining Tbsp coffee liqueur with chocolate ice cream. Pour over first layer of ice cream.
Freeze several hours or overnight until firm.
Serve with remaining warm fudge sauce (if you haven't eaten it all already! yum!).