JSFiddle - React, Tailwind, and code Playground

JavaScript

const arr = Array(61).fill(1).map((num, i) => i + 1);

const split = (input, output = []) => {
	if (!input.length) return output;
  output.push(input.slice(0, 20))
  return split(input.slice(20), output)
}

const final = split(arr);

document.body.innerHTML = JSON.stringify(final);