[Chartjs]-Chart.js doughnut chart tooltip size?

You can change the title font size too.

options: {
  tooltips: {
    titleFontSize: 10,
    bodyFontSize: 10
  }
}

options: {
     tooltips: { bodyFontSize: 20 }
}

For me this was required to go in the library section

{
  ...,
  library: {
    tooltips: {
      ...
    },
  },
  ...
}