How can I change the font (family) for the labels in Chart.JS?

If you wanted to add the font-family to the chart object then you can add it in the options object.

options: {
  legend: {
    labels: { 
      fontFamily: 'YourFont'
    }
  }...}

Here is a link to the docs: https://www.chartjs.org/docs/latest/general/fonts.html

This should be useful: http://www.chartjs.org/docs/. It says "There are 4 special global settings that can change all of the fonts on the chart. These options are in Chart.defaults.global".

You'll need to change defaultFontFamily for the font. And defaultFontColor, defaultFontSize, and defaultFontStyle for color, size, etc.