Try just this:
<iframe src="https://player.twitch.tv/?channel=monstercat&parent=carlos-trevino-dxzy.squarespace.com&parent=djpromote.com&parent=www.djpromote.com" frameborder="0" allowfullscreen="true" scrolling="no" height="378" width="100%"></iframe>
If that doesn’t work my suggestion is to attempt to change your Squarespace domain name to carlostrevino.squarespace.com.