Heat the oil in a sauté pan on medium heat. Add the onion and stir until aromatic. Add the garlic and cook for about another minute.
Add the cut tomatoes and smash them up in the pan with the back of a fork or another crushing tool. Add the water from the can of olives and allow sauce to simmer and reduce a bit, about 10- 15 minutes.
Add the olives and chopped basil and heat through.
Add the cooked pasta and toss until well coated.
Slice the optional cooked chicken on top.
Serve and enjoy!