In a skillet over medium heat, cook the bacon until crisp. Remove to a paper towel-lined plate and dab off the excess grease. Set aside.
Reserve the bacon grease in the skillet. Remove the stem and seeds from the peppers. Finely chop.
Finely chop the celery. Remove the peel of the onion and finely chop. Chop the jalapeño pepper and remove the seeds if desired -- leave them in for extra heat.*
Add the peppers, celery, onion, and jalapeño pepper to the skillet with the reserved bacon grease. Saute the veggies over medium heat until tender. Transfer to the slow cooker.
Add in the three cans of chili beans (undrained and do not rinse), petite diced tomatoes, and tomato paste.
In the same skillet used to cook the bacon and veggies, cook the ground chuck and Italian sausage over medium-high heat until no longer pink. Drain off all the fat and add to the slow cooker.
Add all the seasonings to the crockpot. Crumble the bacon (or chop) into very small pieces and stir that in the crockpot. Or reserve the bacon in the fridge and add at the end. Stir everything together.
Cover and cook on low for 6-8 hours. Taste and adjust seasonings (salt, pepper, chili powder, etc.) Enjoy with fresh cilantro, sour cream and Cheddar cheese.
I use a 6-quart slow cooker and this chili fills it to the top! It makes a lot, which we love to eat throughout a whole week, take to a chili cook-off, or freeze in batches. *The jalapeño pepper(s) adds a lot of heat. Omit or reduce as desired.