Vegetarian chili in a slow cooker

it was so good that I'm not really sure if I want to add ground beef anymore.

1/2 cup olive oil
4 onions, chopped
2 green bell peppers, seeded and chopped
2 red bell peppers, seeded and chopped
4 cloves garlic, minced
1 (14 ounce) package firm tofu, drained and cubed
4 (15.5 ounce) cans black beans, drained
2 (15 ounce) cans crushed tomatoes
2 teaspoons salt
1/2 teaspoon ground black pepper
6 tablespoons chili powder
2 tablespoons dried oregano
2 tablespoons distilled white vinegar
1 tablespoon liquid hot pepper sauce, such as Tabasco™

Heat the olive oil in a large skillet over medium-high heat. Add the onions; cook and stir until they start to become soft. Add the green peppers, red peppers, garlic and tofu; cook and stir until vegetables are lightly browned and tender, the whole process should take about 10 minutes.
Pour the black beans into the slow cooker and set to Low. Stir in the vegetables and tomatoes. Season with salt, pepper, chili powder, oregano, vinegar and hot pepper sauce. Stir gently and cover. Cook on LOW for 6 to 8 hours.