Preheat the oven to 350 degrees F (175 degrees C). Spray two 9x5-inch loaf pans with cooking spray.

Mix cake mix, pecans, bananas, water, vegetable oil, pudding mix, and eggs together in a large bowl with an electric mixer until evenly blended. Pour 1/2 of the batter into each of the prepared loaf pans.

Bake in the preheated oven until a toothpick inserted in the middle of each loaf comes out clean, about 45 minutes.