Using Hardhat Deployment Scripts

const { ethers } = require('hardhat');
const hre = require('hardhat');
require('dotenv').config()  // Store environment-specific variable from '.env' to process.env

function waitforme(milisec) {
  return new Promise(resolve => {
      setTimeout(() => { resolve('') }, milisec);
  })
}

module.exports = async ({ getNamedAccounts, deployments, getChainId }) => {
    const { deploy } = deployments;
    const { deployer } = await getNamedAccounts();
    const artifact = await deployments.getArtifact('NFTContract');
    const chainId = await getChainId();
    const networkName = hre.network.name;

    const result = await deploy('NFTContract', {
      from: deployer,
      contract: {
        abi:artifact.abi,
        bytecode:artifact.bytecode,
        deployedBytecode:artifact.deployedBytecode
      },
      // args: [<constructorArguments>],
      log: true,
      skipIfAlreadyDeployed: true
    });

    if (result.newlyDeployed) {
      // It takes time for etherscan to index newly deployed contracts
      await waitforme(20000);
      await hre.run('verify:verify', {
        address: augustus.address,
        // constructorArguments: [<constructorArguments>],
      });
    }

  };
  module.exports.tags = ['NFTContract'];

require("@nomiclabs/hardhat-waffle");

const PROVIDER_URL = "URL";
// Please don't commit your private keys
// Usually you use a .env file to keep the private key 
// which is still not secure but better
const MAINNET_PRIVATE_KEY = "YOUR PRIVATE KEY";

module.exports = {
  solidity: "0.7.3",
  networks: {
    mainnet: {
      url: PROVIDER_URL,
      accounts: [`${MAINNET_PRIVATE_KEY}`]
    }
  }
};

Running the deployments: yarn compile && yarn hardhat --network mainnet deploy