In a skillet over medium-high heat, add the olive oil and heat until hot. Add the chicken in batches and cook, browning, a couple minutes per side; remove the chicken to a plate using a slotted spoon. Add the garlic and onions to the skillet and cook briefly. Add the chili powder, paprika, cumin and salt to taste. Pour in the tomato sauce and 2 cups water to create a broth. Add the chicken back to the skillet. Bring to a boil, then simmer until the broth is reduced by half.