In a large pot, warm the olive oil over medium heat. Add the chopped onion, red bell pepper, and carrots. Sauté these vegetables, stirring frequently, until they become tender, roughly 7 to 9 minutes. Stir in the minced garlic and finely chopped jalapeño, cooking until their aroma becomes fragrant, about 1 minute.
Incorporate the tomato paste, stirring to coat the vegetables evenly. Add the black beans, kidney beans, and pinto beans, followed by the fire-roasted tomatoes, vegetable broth, chili powder, cumin, and oregano. Season generously with kosher salt and freshly ground black pepper. Bring the mixture to a boil, then reduce the heat to medium-low, allowing the chili to simmer. Stir occasionally, letting the flavors blend and the mixture thicken for around 30 minutes.
Ladle the chili into bowls and garnish with shredded cheddar cheese, a dollop of sour cream, and fresh cilantro leaves before serving.