Heat oil in a medium skillet and add chopped onions. Saute for 4-5 minutes or until browned and soft. During the last minute, stir in the garlic.
In a blender, combine one can of black beans, chicken stock, salsa and cumin. Puree until smooth.
Pour into a large saucepan. Add remaining beans and chicken and bring to a simmer.
Once hot, add cilantro, lime juice and salt and pepper to taste. Stir.
Let simmer for several minutes to allow flavors to blend.
Serve with any of the following garnishes: lime wedges, sour cream, shredded cheese, sliced avocado, minced jalapeno, chopped cilantro, and tortilla chips.
Notes
Crockpot version – use about ¾-1 pound boneless chicken thighs in place of rotisserie chicken. Add everything but the cilantro and lime juice to the pot and cook on low for 5-6 hours. Remove chicken when done and shred. Return the shredded chicken to the pot, add cilantro and lime juice, stir and serve.Instant Pot version – Use 2 large chicken breasts in lieu of rotisserie chicken. Add everything to the instant pot except the cilantro and lime juice. Cover and cook on soup function (or high pressure) for 10 minutes. Quick-release pressure, shred chicken breasts then return to the pot and stir in cilantro and lime juice. Taste and season. If the soup is too liquidy, let it cook on the saute function for a bit longer until slightly reduced.