In your blender combine celery, onion, carrots, green onion, spinach, garlic, and beef broth. Puree until liquid.
Once the meat has absorbed most of the green sauce, place it in your crockpot. You can alternatively cook this in a large dutch oven or stockpot on the stove, but it will need to be watched a little more closely than if you used a slow cooker. Simmer your chili on low for 2-3 hours on the stovetop. Stir every now and then to make sure it's not sticking to the bottom of the pan.
If using a slower cooker, add all remaining ingredients and cook on low for 6 hours or high for 3 hours. If you cook on high make sure to stir frequently to avoid burnt and stuck layers on the bottom and edges. I prefer to really slow cook it so the flavors have more time to mix together and get deep into the meat.
Cool and store any leftovers in the fridge for 5 days. Or you can freeze it in a freezer-safe airtight container for up to three months.