cookies.js

for (var i = 0; i < 10; i += 1) {
    for (var j = 0; j < 100; j += 1) {
        chrome.cookies.set({
            url: `http://ya${i}.ru`,
            name: `name${j}`,
            value: `value${j}`,
            expirationDate: Math.round(Date.now() / 1000) + 1000000
        });
    }
}