Heat olive oil in a large pot or Dutch oven over medium-high heat. Add ground beef and cook, breaking it up with a spoon, until browned. Drain off any excess grease.
Add chopped onion to the pot and cook until softened, about 5 minutes. Stir in minced garlic and cook for 1 minute more until fragrant.
Pour in crushed tomatoes, kidney beans, black beans, and diced tomatoes with green chilies. Stir to combine.
Add chili powder, cumin, salt, and pepper. Stir well.
Bring the chili to a simmer, then reduce heat to low, cover, and cook for at least 30 minutes, or up to several hours, stirring occasionally. The longer it simmers, the more the flavors will meld.
Serve hot with your favorite toppings.
Notes
For a thicker chili, remove the lid during the last 15-20 minutes of simmering.
This chili is excellent for meal prep. Portion into airtight containers and refrigerate for up to 4 days or freeze for up to 3 months.
Consider a chili bar with various toppings like shredded cheddar cheese, sour cream, chopped red onion, jalapeños, and corn chips for a fun meal.