Place dutch oven on stovetop over medium heat. Add 1 tablespoon olive oil and swirl or tilt pot to distribute oil across entire surface. Continue heating pot until oil is hot and shimmery.
When oil is ready, add 1 medium yellow onion (diced) and 1 medium green bell pepper (diced) to pot. Stir to incorporate, then sauté veggies 3 to 4 minutes, stirring occasionally, until veggies have softened and onions are translucent.
When onions are ready, add 1 tablespoon minced fresh garlic. Stir to incorporate, then sauté 30 to 60 seconds or until garlic is fragrant.
Add 1 pound lean ground beef to pot. Cook ground beef, stirring frequently and using spoon to break up beef, until ground beef is browned and crumbled, approximately 5 minutes.
Once ground beef is browned, add 2 tablespoons chili powder, 2 teaspoons cumin, ½ tablespoon smoked paprika, ⅛ teaspoon crushed red pepper flakes, freshly cracked black pepper, and 3 ½ teaspoons salt to pot. Continue cooking ground beef 30 seconds more, stirring constantly to fully incorporate spices into meat.
Pour in 2 cups low-sodium beef broth and stir to incorporate, scraping bottom of dutch oven with spoon to loosen any onions, garlic, or bell pepper that may have stuck to bottom of pot.
Once broth is incorporated, add ½ cup uncooked long-grain white rice, 1 14-ounce can crushed tomatoes, 1 tablespoon tomato paste, and 1 14-ounce can kidney beans. Stir until all ingredients are fully incorporated.
Reduce heat to low. Simmer chili, uncovered, 20 to 25 minutes or until chili has thickened and rice is fully cooked. Stir chili occasionally to prevent sticking or burning.
When chili is ready, portion chili into serving bowls. Top with sour cream, shredded cheddar cheese, chopped red onions, and thinly sliced green onions if desired. Serve warm with optional tortilla chips.