Add all of the ingredients (except for the chocolate chips) in a small jar or Tupperware container.
Place in the fridge overnight.
Adjust and add more milk if you prefer a less thick mixture.
Sprinkle with chocolate chips before serving.
You can also divide the peanut butter serving in half. You can add half of the peanut butter to the jar with the other ingredients prior to placing the jar in the fridge overnight. Add the remaining peanut butter immediately before serving.