I think there is too much tomato paste and the recipe called for lemon and it tastes...off.
Any way to doctor it? I have a virtual VAT of it made ahead for a party! Recipe from The Silver Palate Restaurant cookbook, Chili for a crowd.
Time...if you have it, leave in fridge a day or two, then taste. Flavors may have blended/interacted to create better overall taste
If not, go to plan B, with several alternatives.
1) bulk. Divide this chili in half, make half recipe of original without the acidic elements. Mix, taste, adjust, heat & serve.
2) buffer. Serve with fatty or starchy foods to balance the acidity in the meal if not the dish. Cheese, sour cream, avocado, cornbread.
3) science. Remember ph ratings from chemistry? Acid is low value, base is high. Look up foods that are basic and add some to chili to offset acid. Some sites recommend baking soda, but I haven't tried it so can't give you road-test report.
Good luck and please tell us how you fix this!