Hearty Vegan Slow-Cooker Chili
1 (10 ounce) package frozen chopped spinach, … 1 (15 ounce) can black beans, rinsed and drai… 1 (15 ounce) can garbanzo beans, drained 1 (15 ounce) can kidney beans, rinsed and dra… 1 (8 ounce) can tomato sauce, or more if need… 1 cup frozen corn kernels, thawed 1 cup vegetable broth, or more if needed 1 green bell pepper, chopped 1 red bell pepper, chopped 1 tablespoon dried oregano 1 tablespoon dried parsley 1 tablespoon ground cumin 1 tablespoon olive oil 1 yellow bell pepper, chopped 1 yellow squash, chopped 1 zucchini, chopped 2 (14.5 ounce) cans diced tomatoes with juice 2 (6 ounce) cans tomato paste 2 onions, chopped 4 cloves garlic, minced 6 tablespoons chili powder ½ teaspoon ground black pepper ½ teaspoon salt