In cook-offs which are using “homestyle” rules, anything goes for what you put in. If it’s Texas-style, though, any meat which isn’t beef is disqualifying. (Some cooks will use bacon grease to sauté the meat at the beginning of the recipe, or put pork/porkbones in that they remove before judging, which is perfectly legal.) Many cook-offs are both, and cooks will make one pot of Texas-style and one pot of homestyle and be judged separately on each. Tomato sauce/paste/puree is, BTW, acceptable in Texas-style.
For the curious, here’s my recipe for homestyle chili;
1/4 cup olive oil
1 sweet onion, chopped
4 cloves garlic, minced
1 lb. ground beef chili grind
1 lb. ground pork
1 tbls. salt
1 tbls. black pepper
4 tbls. chili powder
2 tbls. cumin
1 packet Sazon Goya (You can find this at Mexican grocery stores)
1/3rd cup cornstarch, dissolved in 1/3rd cup water
3 fresh jalapeno peppers, chopped
3 Anaheim peppers, seeded and minced
4 serrano peppers, chopped
1 habanero peppers, seeded and minced
1 15 oz. can pinto beans, drained
1 15 oz. can tomato sauce
1 cup beef broth
1 cup chicken broth
1 tsp. white vinegar
1 drop liquid smoke
In a large, thick-bottomed stockpot, warm olive oil over medium-high heat. Add onions, garlic, salt, and pepper, and saute for 3-5 minutes until onions are softened. Add beef and pork, combine thoroughly, and cook until fully browned. (Do NOT drain.)
Add beans and all peppers and stir to mix. Add chili powder, cumin, and Sazon Goya, and stir to mix. Reduce heat to medium-low and add cornstarch drop by drop, as necessary until all the grease in the pot is bound, stirring constantly to prevent scorching.
Add tomato sauce and broth and stir to mix. Bring to boil and add vinegar and liquid smoke.
Reduce heat to low and simmer 1 1/2 - 2 hours, stirring often to prevent scorching, until sauce has thickened and peppers have softened.
The most important thing is to keep the heat low and stir often enough to prevent the bottom of the pan from scorching. Having a thick-bottomed pot will also help here. If you do happen to scorch the chili, transfer it to a new pot as soon as possible and add a couple spoonfuls of peanut butter - it neutralizes any burnt flavor left over and won’t be noticeable in the final product.