Prepare the cake mix according to package directions, adding the chopped nuts plus 1/3 to 1/2 cup more water than instructed, making a thick, flowing batter.
Peel, core and dice the apples. Melt the butter in a saute pan and, when it stops foaming, add the apples and toss over medium heat. Cover, lower heat and cook until soft but still slightly crisp. Squeeze lemon juice over the apples.
Heat the waffle iron and spray the grids with nonstick vegetable spray. Use a 1/4 cup measure to pour a puddle of batter in the center of each grid. Cook the waffles until they are firm enough to remove from the waffle iron. Put on plates.
Spoon the hot apples over the waffles. Top with a spoonful of sour cream, if desired.