Check the labels on the canned black beans. Carbs can vary between the brands. I found one type that only has 33 net carbs per can.
Serving Size: 1 (427) g
Servings Per Recipe: 2
Calories: 451.3
Calories from Fat 138 g 31 %
Total Fat 15.4 g 23 %
Saturated Fat 8.4 g 41 %
Cholesterol 72.6 mg 24 %
Sodium 638.9 mg 26 %
Total Carbohydrate 41.8 g 13 %
Dietary Fiber 14.1 g 56 %
Sugars 1.9 g 7 %
Protein 38.4 g 76 %