Heat a large pot or Dutch oven over medium heat. Add the ground beef and cook, breaking it apart with a wooden spoon, until it is no longer pink, about 8–10 minutes. If needed, drain any excess grease.
Add the diced onion and cook, stirring occasionally, until it becomes translucent, about 5–7 minutes. Stir in the minced garlic and cook for 1 minute until fragrant.
Add the kidney beans, stewed tomatoes (including their juices), chili seasoning, salt, and pepper. Stir well to combine all ingredients.
Bring the mixture to a boil, then reduce the heat to low. Simmer gently, stirring occasionally, until the vegetables are tender and the chili is thoroughly heated, about 15–20 minutes.
Dress up your chili with your favorite toppings and serve!