Drain cannellini (or other white) beans from a can and empty into a large saucepan. Heat on low. Add bagged spinach and stir. While spinach is wilting, shred and add cooked chicken. Turn heat up to medium. Add tinned tomatoes or a few spoonfuls (not too much!) of red sauce for flavour and moisture.
Verdict: Delicious, nutritious, mess-free, and done in five minutes. Excellent.