Combine sugar and cinnamon. Coat biscuit pieces in sugar-cinnamon mixture.
Place coated biscuit pieces into 2 mini loaf pans.
In a mixing bowl, add brown sugar to melted butter and mix until sugar dissolves. Pour butter mixture into loaf pans. Sprinkle chopped walnuts on top. Cover with aluminum foil.
Place steamer rack in bottom of cooker. Pour in water. Place mini loaf pans on top of rack. Close and lock lid.
Set pressure cooker to "bake", adjust time to 22 minutes, and press "start/stop".
When done, natural release, 5 minutes, then quick release to make sure all pressure is released before opening lid. Carefully open lid
and remove loaf pans. Serve.