I am trying to build a two-dimensional chess game and found that there are Unicode for chess pieces built into HTML, is it possible to use those inside a canvas? If so, how?
Unicode by itself doesn't have anything to do with HTML, though HTML supports Unicode character escapes.
Regardless, you can just render text in <canvas>:
const canvas = document.querySelector("canvas");
const ctx = canvas.getContext("2d");
const size = 16;
ctx.font = `${size}px sans-serif`;
ctx.fillText("\u2654", 0, size); // See https://en.wikipedia.org/wiki/Chess_symbols_in_Unicode<canvas></canvas>