How to capture all 13 digits after that regex non-capture group
If you're confident that you have consistent content try: /(?<=SKU:\s)[\dA-Z]{13}/g
const items = document.querySelectorAll('li');
let SKU = [...items].flatMap(li => li.textContent.match(/(?<=SKU:\s)[\dA-Z]{13}/g));
console.log(SKU)<li class="cart__item">SKU: MLB2046549757 | NAME: Notebook Multilaser Legacy Book Pc310 Preta 14.1 , Intel Celeron N3000 4gb De Ram 64gb Ssd, Intel Hd Graphics 1366x768px Windows 10 Home | PRICE: $1415</li>
<li class="cart__item">SKU: MLB2046585666 | NAME: Notebook Multilaser Legacy Book Pc310 Preta 14.1 , Intel Celeron N3000 4gb De Ram 64gb Ssd, Intel Hd Graphics 1366x768px Windows 10 Home | PRICE: $1415</li>Try this:
(SKU:\s)(.{13})
(?<=SKU:\s)(.{13})
2nd regex will result only the 13 positions after SKU: See demo
-Cheers!